How do HIV testing technologies work. What are the different types of HIV tests available. How accurate are rapid HIV tests. What is the window period for HIV testing. How long does it take to get HIV test results.

Understanding HIV Testing Technologies: An Overview

HIV testing technologies play a crucial role in determining whether a person has contracted the human immunodeficiency virus. These tests have evolved significantly over the years, offering various methods to detect HIV infection. In Canada, several types of HIV testing technologies are employed, each with its unique characteristics, including detection mechanisms, window periods, and result turnaround times.

Testing for HIV can be conducted in diverse settings across Canada, ranging from hospitals and health clinics to community centers. Moreover, recent advancements have made it possible for individuals to perform self-tests in the privacy of their own homes.

The Basics of HIV Testing: Blood Sample Collection

The foundation of HIV testing lies in the analysis of a person’s blood sample. There are two primary methods of collecting blood for HIV testing:

• Standard testing: A vial of blood is drawn from a vein and sent to a laboratory for analysis.
• Rapid testing: A single drop of blood is obtained through a finger prick for immediate testing.

While the standard testing method is more common and involves laboratory analysis, rapid tests provide quicker results and can be performed on-site or at home.

Dried Blood Spot (DBS) Technique

A less common but noteworthy method of blood collection is the dried blood spot (DBS) technique. This approach involves collecting blood samples from a finger prick as blots on a card. The blood spots are then dried at room temperature and mailed to a public health laboratory for analysis.

DBS samples offer several advantages:

• Stability: The samples remain stable at room temperature and don’t require refrigeration.
• Convenience: Particularly useful for testing in rural and remote areas.
• Ease of transport: Can be easily mailed to laboratories for analysis.

However, the use of DBS in Canada is currently limited due to the scarcity of public health laboratories equipped to process these cards.

Laboratory Testing: The Gold Standard in HIV Detection

Laboratory testing remains the most comprehensive and reliable method for HIV detection. The process typically involves two stages: screening and confirmation.

Screening Tests: The First Line of Detection

When a blood sample arrives at the laboratory, it undergoes an initial screening test. In Canada, all laboratories utilize fourth-generation tests for this initial screening. These tests are designed to detect both HIV antibodies and the p24 antigen, allowing for earlier detection of HIV infection compared to previous generations of tests.

Is a non-reactive screening test result conclusive? In most cases, a non-reactive result (also referred to as testing negative or HIV-negative) indicates that the person does not have HIV. No further testing is usually required, and the negative result is communicated to the healthcare provider or clinic that ordered the test.

Confirmatory Tests: Ensuring Accuracy

If the screening test yields a reactive result (indicating potential HIV infection), a confirmatory test is performed on the same blood sample. This second test serves to verify the accuracy of the initial screening result.

The Geenius HIV 1/2 Confirmatory Assay is commonly used for this purpose. It can differentiate between HIV-1 and HIV-2 infections, providing more detailed information about the specific type of HIV present.

Only after a positive confirmatory test result is a person considered to be HIV-positive. This result is then communicated to the healthcare provider or clinic for further action and patient counseling.

Rapid HIV Testing: Quick Results for Immediate Action

Rapid HIV tests have revolutionized the field of HIV detection by providing quick results, often within minutes. In Canada, there are two types of rapid HIV tests available: point-of-care (POC) tests and self-tests.

Point-of-Care (POC) Testing

POC tests offer the advantage of providing results during the same visit, eliminating the need for patients to return for their results. The INSTI HIV-1/HIV-2 Antibody Test is currently the only POC test approved for use in Canada.

How does the INSTI HIV-1/HIV-2 Antibody Test work? This test requires a single drop of blood from a finger prick. The blood sample is then analyzed on-site, with results available within minutes.

• Non-reactive result: If the test indicates no HIV infection, no further testing is typically required, and the person can be immediately informed of their HIV-negative status.
• Reactive result: A reactive POC test result is not considered a final diagnosis. In this case, a vial of blood must be drawn and sent to a public health laboratory for confirmatory testing.

It’s important to note that in some cases, even with a non-reactive POC test result, additional laboratory testing may be recommended if there’s reason to believe the person might have been recently exposed to HIV and could be in the window period.

HIV Self-Testing: Empowering Individual Health Management

HIV self-tests represent a significant advancement in HIV testing technology, allowing individuals to test themselves for HIV in the privacy of their own homes or other locations. In November 2020, Canada approved its first HIV self-test for use and sale.

The INSTI HIV Self Test, which uses the same technology as the POC test, requires a single drop of blood to detect HIV antibodies. This test provides results within minutes, offering a convenient and discreet option for those who might be hesitant to visit a healthcare facility for testing.

How should one interpret self-test results?

• Non-reactive result: If the self-test result is non-reactive and the person is outside the window period, no further testing is typically required.
• Reactive result: A reactive self-test result necessitates confirmatory testing. The individual should seek out professional medical care for a confirmatory test and further guidance.

Understanding the Window Period in HIV Testing

The window period is a crucial concept in HIV testing, referring to the time between potential exposure to HIV and when a test can accurately detect the virus. This period varies depending on the type of test used and the individual’s immune response.

Window Periods for Different HIV Test Types

• Fourth-generation laboratory tests: Can detect HIV as early as 18 days after exposure.
• Third-generation rapid tests (including POC and self-tests): Can typically detect HIV about 3 to 4 weeks after exposure.

Why is understanding the window period important? If a person gets tested during the window period, they may receive a false-negative result. This means the test may not detect HIV even if the person is infected. For this reason, it’s often recommended to get retested after the window period has passed to ensure accurate results.

Turnaround Time for HIV Test Results

The time it takes to receive HIV test results varies depending on the type of test used:

• Laboratory testing: Results typically take 1 to 2 weeks.
• Point-of-care testing: Results are available within minutes during the same visit.
• Self-testing: Results are available within minutes at home.

For laboratory testing, the longer turnaround time is due to the process of sending the sample to the lab, conducting the tests, and communicating the results back to the healthcare provider. In contrast, rapid tests provide almost immediate results, which can be particularly beneficial in situations where quick decision-making is crucial.

Accuracy and Reliability of HIV Testing Technologies

The accuracy of HIV tests is generally very high, but it’s important to understand that no test is 100% perfect. Several factors can influence the accuracy of HIV tests:

• The type of test used
• The timing of the test in relation to potential exposure (window period)
• The proper administration and interpretation of the test

Are laboratory tests more accurate than rapid tests? Generally, laboratory tests are considered the most accurate, especially when combining screening and confirmatory tests. Fourth-generation laboratory tests can detect HIV earlier than rapid tests and have a very low rate of false results.

Rapid tests, including POC and self-tests, are also highly accurate when used correctly and outside the window period. However, because they are third-generation tests, they may not detect very early HIV infections as reliably as fourth-generation laboratory tests.

Sensitivity and Specificity of HIV Tests

Two key measures of test accuracy are sensitivity and specificity:

• Sensitivity: The ability of a test to correctly identify those with HIV (true positive rate).
• Specificity: The ability of a test to correctly identify those without HIV (true negative rate).

Modern HIV tests, both laboratory and rapid tests, typically have sensitivity and specificity rates above 99% when used correctly and outside the window period. However, it’s crucial to remember that any reactive result from a rapid test should always be confirmed with laboratory testing.

The Future of HIV Testing Technologies

As research in HIV detection continues to advance, we can expect to see further improvements in testing technologies. Some areas of ongoing development include:

• Shorter window periods: Researchers are working on tests that can detect HIV even earlier after exposure.
• Improved self-testing options: Future self-tests may offer greater accuracy and easier interpretation of results.
• Integration with digital health platforms: HIV tests may become more integrated with smartphone apps and other digital health tools for better tracking and follow-up.
• Multiplex testing: Development of tests that can simultaneously detect HIV and other sexually transmitted infections.

These advancements aim to make HIV testing more accessible, accurate, and user-friendly, ultimately contributing to better HIV prevention and treatment strategies.

As HIV testing technologies continue to evolve, they play an increasingly important role in public health efforts to control the spread of HIV. By providing accurate, timely results, these tests empower individuals to take control of their health and access appropriate care when needed. Whether through laboratory testing, point-of-care tests, or self-testing options, the goal remains the same: to detect HIV infections early and link individuals to care, ultimately improving health outcomes and reducing HIV transmission.

HIV testing technologies | CATIE

HIV testing technologies are used to determine if a person has HIV. Several types of HIV testing technologies are used in Canada. These tests differ in several ways, including how the test detects HIV infection, the length of its window period and how long it takes to receive results.

People can be tested for HIV in a variety of different settings in Canada, including hospitals, health clinics and the community. They also now have the option to test themselves in their own home.

How are testing technologies used to diagnose HIV infection?

To test for HIV, a sample of a person’s blood is taken. With the most common test, a vial of blood taken from a vein is sent to a laboratory to be tested for HIV (standard testing). There are also rapid tests available, which use a drop of blood from a finger prick to test for HIV immediately after the sample is taken.

Laboratory testing

Most HIV testing of blood samples is conducted in a laboratory. Typically, a blood sample is drawn from a person’s vein and sent to a public health laboratory for analysis. A much less common method of collecting blood samples is through dried blood spot (DBS). This approach uses samples of blood from a finger prick that are collected as blots on a card. The blood spots are dried at room temperature and mailed to a public health laboratory. Currently, this collection technique is in limited use in Canada because very few public health laboratories can process the DBS cards to prepare the blood for analysis. DBS samples are very stable once collected and do not need to be refrigerated, which makes this sampling approach particularly useful in rural and remote areas.

Regardless of how the blood was collected, the first test used in a laboratory to analyze a blood sample is referred to as a screening test. All laboratories in Canada use a fourth-generation test to screen blood samples.

If the screening test indicates that the person who gave the blood sample does not have HIV (also known as a non-reactive test result or testing negative or HIV negative), no further testing is normally performed. The negative result is sent back to the healthcare provider or clinic that ordered the test so that the person who tested can be given the result.

If the screening test indicates that the person may have HIV (also known as a reactive test result), then another test is performed on the same sample to confirm that the result of the screening test was correct. If the confirmatory test indicates that the person is HIV positive, the positive result is sent back to the healthcare provider or clinic that ordered the test so that the person who tested can be given the result.

It can take up to one or two weeks for a person to receive their test result when laboratory testing is conducted.

Rapid testing

There are two types of rapid HIV tests in Canada, the point-of care (POC) test and the self-test. Rapid tests are third-generation screening tests. Currently in Canada the POC test and the self-test use the same technology.

Point-of-care testing

Point-of-care tests can provide results within minutes, so the client can be given the result of the test during the same visit. There is only one POC test approved for use in Canada, the INSTI HIV-1/HIV-2 Antibody Test. This test requires a drop of blood from a finger prick to test for HIV.

If the POC test indicates no HIV infection is present (a non-reactive test result), then no further testing is normally performed and the person who tested can be immediately informed of their HIV-negative result. However, if the POC test indicates that a person has HIV (a reactive test result), this is not a final diagnosis. Instead, a vial of blood must be taken and sent to a public health laboratory for confirmatory testing. It can take up to one or two weeks to receive the results from confirmatory testing.

In some cases, if the POC test result is non-reactive and there is reason to believe the person being tested may have recently been exposed to HIV (and is in the window period – see below for more details), a vial of blood can be taken and sent to a laboratory for testing.

Self-testing

HIV self-tests allow people to test themselves for HIV in their home or other locations and can provide results within minutes. The first HIV self-test was licensed for use and sale in Canada in November 2020. The INSTI HIV Self Test uses the same technology as the POC test and requires a single drop of blood to test for HIV. As with the POC test, if the self-test result is non-reactive then no further testing is required, as long as the person doing the test is out of the window period. A reactive test result requires a confirmatory test and will require the person who uses the self-test to seek out confirmatory testing.

Confirmatory tests

The Geenius HIV 1/2 Confirmatory Assay is now used by public health laboratories in Canada and has replaced the Western blot as the standard test used to confirm a reactive HIV screening test.

Other types of confirmatory testing may be used in certain circumstances, such as when a test result is indeterminate. These include nucleic acid amplification tests (NAATs) and p24 antigen-only tests.

What is the window period and how does it differ between tests?

No test can detect HIV immediately after infection. The time between when a person is exposed to HIV and when an HIV test can tell they have HIV is called the window period. The window period can vary between two weeks and three months. The length of the window period varies from person to person and also depends on the type of test used. Some people develop markers of HIV infection that are detected by HIV tests slowly and some people develop them more rapidly. Once these markers of HIV infection are present in amounts that the test can detect, the window period is over.

If someone has had a recent exposure to HIV and gets tested for HIV during the window period, the test result may come back as negative (non-reactive) even though the person actually has HIV. This would happen if their body has not started producing the markers of HIV infection at levels that are detectable by the test. When a test result is negative after a recent exposure to HIV, the person should be retested at the end of the window period to confirm they are HIV negative.

The most commonly used HIV tests in Canada detect different markers of HIV infection. Some look for HIV antibodies (proteins produced by the body’s immune system in response to HIV infection) only, while another looks for both antibodies and the p24 antigen (a specific part of the virus itself). All antibody tests in Canada can detect both HIV-1 (the most common type of HIV) and HIV-2.

Rapid HIV screening tests, including both the POC and self-test, are third-generation tests and detect HIV antibodies. The window period for these tests is between three weeks and 12 weeks. These tests can detect HIV antibodies in 50% of people by about 22 days after exposure to HIV and 99% of people by 12 weeks after exposure.

The antibody–antigen combination test is the fourth-generation screening test used in public health laboratories in Canada. This test detects both the p24 antigen and antibodies. The window period for this test is between two weeks and 6.5 weeks. It can detect HIV in 50% of people by 18 days after exposure to HIV and in 99% of people by 44 days after exposure. This means that the fourth-generation test can find an infection at least a week earlier than third-generation POC and self-tests in most people. This is because the p24 antigen is detectable before HIV antibodies. In addition, the fourth-generation test can rule out an HIV infection 5.5 weeks earlier than third-generation tests.

Most people will get an accurate test result with third- or fourth-generation tests three to four weeks after an exposure to HIV. However, not everyone will. It’s important to test again at the end of the window period to rule out an HIV infection.

The Geenius confirmatory assay can detect HIV infection in 50% of people by 33 days after exposure to HIV and in 99% of people by 58 days after exposure.

How accurate are HIV tests?

HIV tests are very accurate. Once confirmatory testing has been performed, the chance of a positive result being false is essentially zero.

Sensitivity and specificity

Sensitivity and specificity are measures of the accuracy of an HIV test.

Sensitivity is the chance that a positive test result will correctly indicate that a person has HIV. This means that if the person has HIV, the test will detect it. Higher sensitivity means there is a lower chance of a false-negative result (testing negative when actually HIV positive).

Specificity is the chance that a negative test result will correctly indicate that a person does not have HIV. This means that if the person does not have HIV, the test result will be negative. Higher specificity means there is a lower chance of a false-positive result (testing positive when actually HIV negative).

HIV screening tests used in Canada (including third- and fourth-generation tests) all have a sensitivity of up to 99.9%. In other words, if 1,000 HIV-positive people were tested for HIV, 999 would correctly test positive and one would incorrectly test negative. High sensitivity is ideal for a screening test because it effectively rules out people who don’t have HIV (as long as they are outside the window period). Since the vast majority of people who get tested for HIV are actually HIV negative, the chance of a negative result being false is extremely low.

HIV screening tests used in Canada have a slightly lower specificity of up to 99.5%. In other words, if 1,000 HIV-negative people were tested, 995 would correctly test negative and five would incorrectly test positive. Since the specificity is lower, this means there is a higher chance of false positives with the screening tests. This is why all positive screening test results are sent for confirmatory testing with a test that has a very high specificity.

The Geenius assay has a specificity of 100%. This means that the chance of a false-positive result after confirmatory testing is essentially zero.

References

1. bioLytical. INSTI: the world’s fastest HIV test. Richmond (BC): bioLytical; 2019. Available from: http://biolytical.com/products/insti-hiv-1hiv-2/?country=CA
2. Public Health Agency of Canada (PHAC).  HIV screening and testing guide. Ottawa: PHAC; 2013. Available from: http://www.catie.ca/sites/default/files/EN_HIV-Screening-Guide-2013.pdf
3. Centers for Disease Control and Prevention. Types of HIV tests. Atlanta: CDC. Available from: https://www.cdc.gov/hiv/basics/hiv-testing/test-types.html
4. Busch MP, Satten GA. Time course of viremia and antibody seroconversion following human immunodeficiency virus exposure. American Journal of Medicine. 1997;102(5B):117-124; discussion 125–126.
5. Delaney KP, Hanson DL, Masciotra S et al. Time until emergence of HIV test reactivity following infection with HIV-1: implications for interpreting test results and retesting after exposure. Clinical Infectious Diseases. 2017;64:53–59
6. Bio-Rad. Geenius^™ HIV 1/2 Confirmatory Assay. A qualitative assay for the confirmation and differentiation of individual antibodies to HIV-1 and HIV-2 in whole blood, serum, or plasma specimens. Marnes-la-Coquette, France: Bio-Rad; 2013. Available from: https://www.bio-rad.com/webroot/web/pdf/inserts/CDG/en/883601_EN.pdf
7. Pant Pai N, Balram B, Shivkumar S et al. Head-to-head comparison of accuracy of a rapid point-of-care HIV test with oral versus whole-blood specimens: a systematic review and meta-analysis. Lancet Infectious Diseases. 2012;12(5):373–380.

HIV testing – Mayo Clinic

Overview

Human immunodeficiency virus (HIV) testing determines whether you’re infected with HIV, a virus that weakens your immune system and can lead to acquired immunodeficiency syndrome (AIDS).

Some HIV tests check for antibodies that your immune system produces in reaction to HIV infection. Other HIV tests look for evidence of the virus itself. Rapid tests can produce results within 20 minutes.

Researchers continue to improve the sensitivity of tests (how well they detect HIV infection) and how long the tests take to provide results. Guidelines for testing change as tests improve.

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Why it’s done

HIV testing is essential for slowing the spread of HIV infection. Many people are unaware that they’re infected with HIV, so they may be less likely to take precautions to help prevent spreading the virus to others.

Also, early diagnosis often results in earlier treatment with drugs that may delay the progression to AIDS.

The Centers for Disease Control and Prevention (CDC) recommends that everyone ages 13 to 64 years be tested for HIV. This can be done during visits with a health care provider or through community HIV testing centers.

HIV testing is particularly important for pregnant women because they can pass the virus to their babies during pregnancy or delivery or through breast-feeding. Taking medication that combats HIV during pregnancy and delivery greatly reduces the risk that you’ll transmit the virus to your baby.

How often should you be tested?

The CDC recommends at least one HIV test for everyone ages 13 to 64 years. Yearly testing is recommended if you’re at higher risk of infection. The CDC recommends that sexually active gay and bisexual men consider testing every three to six months.

Consider HIV testing yearly and before having sex with a new partner if you:

• Have had unprotected vaginal, oral or anal sex with more than one sexual partner or with an anonymous partner since your last screening
• Are a man who has sex with men
• Use intravenous (IV) drugs, including steroids, hormones or silicone
• Have been diagnosed with tuberculosis or a sexually transmitted infection (STI), such as hepatitis or syphilis
• Exchange sex for money or drugs
• Have had unprotected sex with someone who falls into any of the above categories

Also consider getting tested if you:

• Have been sexually assaulted
• Are pregnant or planning to get pregnant

How you prepare

No special preparations are necessary for HIV testing. Many different settings offer testing including:

• Health care providers’ offices
• Community health centers
• Sexually transmitted disease treatment clinics
• Substance abuse treatment programs
• Pharmacies

If you don’t have health insurance, some sites offer free testing.

To find a site near you, use the HIV.gov HIV services locator.

What you can expect

HIV is usually diagnosed by testing your blood or a sample of cells taken with a swab from inside your cheek for the presence of antibodies to the virus.

HIV tests vary in how soon they are able to detect infection. The time between when you get the virus and when it can be detected is called the window period. It can take up to three to 12 weeks for your body to make enough antibodies for an antibody test to detect HIV infection.

It usually takes a few days to a few weeks to get results of an HIV test, although rapid HIV tests can produce results in about 20 minutes.

Regardless of the type of screening test used, if you have an initial positive result you’ll need follow-up testing to establish an HIV diagnosis.

Rapid HIV testing

Several rapid tests offer highly accurate information within as little as 20 minutes. These tests look for antibodies to HIV using either:

• A sample of your blood, drawn from a vein or a finger prick
• Fluids collected on a treated pad that is rubbed on your upper and lower gums

A positive reaction on a rapid test requires an additional blood test to confirm the results.

Home HIV testing

Home testing involves:

• Collecting an oral fluid sample by swabbing your mouth
• Using a kit to test the sample yourself

You’ll get results in 20 minutes. A positive test result means you’ll need a follow-up test. The maker of the test offers confidential counseling and referral to follow-up testing sites.

A home blood test is no longer available.

Clinic or lab HIV testing

Doctors’ offices or other health care settings will likely follow the CDC recommendations for testing:

• If this is your initial test, you will be given a combination HIV antigen/antibody test.
• If this test is positive, you will then be tested with a second HIV antibody test. This test can tell the difference between the two most common types of HIV, HIV-1 and HIV-2.
• If these two test results conflict, a third test called an HIV-1 RNA test (nucleic acid amplification test) will look directly for HIV in your blood.

No test can confirm HIV infection immediately after you’re exposed. Tests that provide the earliest results are those that:

• Look for antigens — proteins that develop within the first few weeks after infection
• Evaluate your blood for genetic material from the virus

Tests that detect antibodies take longer. To get accurate results, you’ll need to have been infected for at least three weeks.

Results

False-positive and false-negative test results can occur. Doctors will use a variety of tests in sequence (an algorithm) until they determine for certain that you are either HIV-negative or HIV-positive.

Negative HIV test results

A negative test result from HIV testing may mean one of two things: You don’t have HIV, or it’s too soon yet to tell.

If you were only recently exposed to HIV, you could test negative for HIV antibodies because your body hasn’t had time to create them yet. You’ll need to be retested for HIV antibodies in three months, and until then, practice safe sex.

Positive HIV test results

If you test positive for HIV on both the initial and follow-up testing, it confirms that you are HIV-positive.

Although there’s no cure for HIV/AIDS, treatment has come a long way in the past few decades, offering extended and improved quality of life for many. If you are infected with HIV and receive up-to-date treatment, you can have a near-normal life expectancy. Early treatment can help you stay well and prevent or delay the onset of AIDS. Tell your partners if you test positive for HIV because they will need to be evaluated and possibly treated, as well.

Jan. 10, 2020

High accuracy of home-based community rapid HIV testing in rural Malawi

J Acquir Immune Defic Syndr. Author manuscript; available in PMC 2011 Dec 30.

Published in final edited form as:

PMCID: PMC3248920

EMSID: UKMS40313

, MA MSc PhD,^a,b, DipBMS,^a, BSc,^a, MSc,^b, MB BSc MSc PhD,^a,b, PhD FRCP,^b, MBChB DTM&H MSc FFPHM,^a,b and , MB ChB FRCP PhD^a,b

Anna M MOLESWORTH

^aKaronga Prevention Study, PO Box 46, Chilumba, Karonga District (Malawi)

^bLondon School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT (UK)

Richard NDHLOVU

^aKaronga Prevention Study, PO Box 46, Chilumba, Karonga District (Malawi)

Emmanuel BANDA

^aKaronga Prevention Study, PO Box 46, Chilumba, Karonga District (Malawi)

Jacqueline SAUL

^bLondon School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT (UK)

Bagrey NGWIRA

^aKaronga Prevention Study, PO Box 46, Chilumba, Karonga District (Malawi)

^bLondon School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT (UK)

Judith R GLYNN

^bLondon School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT (UK)

Amelia C CRAMPIN

^aKaronga Prevention Study, PO Box 46, Chilumba, Karonga District (Malawi)

^bLondon School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT (UK)

Neil FRENCH

^aKaronga Prevention Study, PO Box 46, Chilumba, Karonga District (Malawi)

^bLondon School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT (UK)

^aKaronga Prevention Study, PO Box 46, Chilumba, Karonga District (Malawi)

^bLondon School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT (UK)

Correspondence and requests for reprints: Neil French, Karonga Prevention Study, PO Box 46, Chilumba, Malawi (telephone: +265 (0)888 263100; ku. ca.mthsl@hcnerflien)See other articles in PMC that cite the published article.

Abstract

Objective

To assess the performance of rapid HIV antibody tests when used as part of a home-based community-wide counselling and testing strategy in northern Malawi.

Design

A cross-sectional population survey of HIV infection, 2007-2008.

Methods

Adults aged 15 or over in a demographic surveillance area were counselled and then offered an HIV test at their home by government certified counsellors. Two initial rapid tests (Detemine™ and Uni-Gold™) were performed on all samples, and a third, tie-breaker test (SD Bioline) used to resolve discordant results. All people who wanted to know were post-test counselled and informed of their results, with referral to local clinical services if found to be HIV positive. Laboratory quality control comprised re-testing all positive and every tenth negative venous blood sample collected.

Results

A total of 10819 adults provided venous blood samples for HIV-testing, of whom 7. 5% (813) were HIV positive. The accuracy of the parallel testing strategy used was high, with 99.6% sensitivity, 100.0% specificity, 99.9% positive predictive value and 99.9% negative predictive values.

Conclusion

Face-to-face rapid testing by health personnel with minimum training, at the clients’ home performs well when used on a wide scale in the community setting.

Keywords: HIV serodiagnosis, quality control, home care, population surveillance, Malawi

Introduction

Rapid HIV antibody tests are widely used for a range of public health and clinic purposes. The rapid tests are relatively easy to perform with minimum equipment and training; and results can typically be obtained within 20 minutes, making the rapid tests well-suited for use in settings where trained laboratory technicians and specialist equipment may be limited [1,2]. In Africa, evaluation of the performance of rapid tests in the research setting, including in mobile and community-based health clinics and information centres, have shown high sensitivity and specificity [1,3,4]; however their performance in the home-based community setting is unclear. Uncertainties have, moreover, been expressed over the accuracy of rapid tests performed in mobile laboratories set up in local buildings or tents in Rakai District, Uganda [5]. In that report an unacceptably high rate of false positive results was found (43.7%, 129 of 295, total 1517 samples), attributed by the authors to the classification of weak positive bands from Determine™ HIV-1/2/O (Abbott Laboratories, Abbott Park, IL) and Uni-Gold™ Recombinant HIV-1/2 (Trinity Biotech, Bray, Ireland) tests as a positive result, when in fact they should be negative.

In Malawi, rapid tests have been incorporated into the national scale up of HIV Testing and Counselling (HTC) and the provision of anti-retroviral therapy (ART) through government services, both of which are free at the point of delivery [6]. With an increasing emphasis on universal testing and promotion of early initiation of antiretroviral therapy [7], a greater amount of HIV testing will need to be performed at, or closer to the home to increase numbers of tests and access for those least able to seek facility –based testing [8]. This requires confidence in the testing procedure. Home based testing is being introduced in several African countries [9,10,11,12] as a means to increasing uptake of testing [13]. Whilst making testing accessible by this approach appears to be feasible and desired by individuals, accuracy of this procedure will need to be carefully and regularly assessed, to ensure accuracy is equal or better than laboratory based testing. We report our experience of home-based community HIV rapid testing in Karonga District, northern Malawi.

Methods

Setting and Design

The Karonga Prevention Study (KPS) is a community-based research site, situated in Chilumba, a small lakeshore settlement in Karonga district in rural northern Malawi. The site includes a laboratory that functions to international standards. A population of approximately 33,500 individuals in an area close to Chilumba has been under continuous demographic surveillance since September 2004 [14]. HIV prevalence in adults in this area in 2006 was estimated at 11. 6% [15]. Here we report on an home-based cross-sectional survey of HIV in adults, which took place in the same area between September 2007 and October 2008, as part of a four year study to assess the impact of ART on HIV transmission in the study population.

All homes in the study area were visited village-by-village; in each village, community sensitization in relation to the study took place shortly before home visits. Any person in the study population who was aged 15 years or over at the time of the household visit was eligible for inclusion in the survey. The survey interviews and HTC were conducted by counsellors who had been trained and certified by Ministry of Health staff to perform HIV counselling, whole-blood rapid testing and specimen collection by finger-prick, using standard training procedures [6]. At each home the study was introduced and explained to all members, participants who, after pre-test counselling, consented to HIV-testing were asked to provide a venous blood sample, with finger-pricks offered as an alternative if the participant preferred. The whole blood was then tested immediately for HIV at the home, all participants who wanted to know were post-test counselled and informed of their results, with referral to local clinical services if found to be HIV positive.

Community-based rapid testing

In Malawi, a whole-blood testing strategy for HIV-1 and HIV-2 is recommended and can be performed by non-laboratory health personnel with minimum basic training, provided that minimum standards for quality assurance are in place [6]. Until May 2008 a parallel testing strategy was used. This strategy is based on performing two initial rapid tests simultaneously on all samples and a third rapid test used only if the results are discordant; if any two rapid test results are concordant, that result is taken as the final rapid test result and reported to the client. After May 2008 a serial testing strategy was introduced after analysis and research which determined that this approach was appropriate [6]. Under the serial testing strategy, one initial rapid test is performed on all samples, a second rapid test is only performed if the first result is positive or inconclusive, and a third performed only if the first two results are discordant. Under both testing strategies the approved rapid tests combined Determine™ HIV-1/2 (Abbott Japan Co Ltd, Tokyo, Japan) with Uni-Gold™ HIV (Trinity Biotech PLC, Bray, Ireland) as the first and second rapid tests respectively, using SD Bioline HIV 1/2 3.0 (Standard Diagnostics Inc, Kyonggi-do, Korea) as a third tie-breaker. All three rapid tests used in Malawi are a one step, visual test for the detection of antibodies to HIV types 1 and 2 in human serum, plasma or whole blood; the test kits (including test device and reagent) can be stored between 2-27°C; they have been reported to have sensitivities and specificities of, respectively, 100% and 99.4% (Determine™), 100% and 100% (Uni-Gold™), and 100% and 99.3% (SD Bioline) when evaluated under standard operational conditions [16,17].

The testing protocol followed by the HIV sero-survey followed the Malawi Ministry of Health guidelines for whole-blood parallel rapid testing, throughout the entire survey round, except that whole venous blood (taken by paramedical staff who had been certified by the Malawi Medical Council to perform phlebotomy), was used to perform the rapid test rather than finger-prick specimens, as this facilitated further laboratory-based HIV-related viral testing, including quality control testing. Determine™, Uni-Gold™ and SD Bioline test kits were stored in a cold room in the laboratory at 4-8° C until ready for use in the community setting, then carried at ambient temperatures to the field; counsellors took with them to the field sufficient supplies to meet at least one day’s needs and restocked when necessary.

At the home, counsellors were required to use a flat, dry surface for the rapid tests according to manufacturers’ guidelines, and to protect the rapid tests from environmental contamination by keeping the test devices inside a closed box while waiting for the results. The blood sample was collected in a S-Monovette® EDTA tube (Sarstedt, Nümbrecht, Germany), and from this placed immediately on the test device using a disposable plastic pipette. A mechanical timer was used, and the counsellors were instructed to read and interpret rapid test results 20 minutes after having added reagents, consistent with the manufacturers’ instructions. For all rapid test devices, counsellors were instructed that any band in the positive region was to be considered reactive to HIV irrespective of the strength of the band; if the rapid test was uninterpretable by virtue of a failed control band it was to be considered inconclusive, according to the manufacturers’ instructions. Tests were performed for one participant at a time, or together for a couple, in which latter situation the test devices were labelled with a marker pen to distinguish between the male and female partners and hence reduce the risk of muddling of test results. Test results were transcribed onto a dedicated rapid-test form, with the outcome of each interview identified by a unique study number, rather than by the participant’s name. Specimens were transported at ambient temperature to the laboratory at KPS at the end of the working day, refrigerated at 2-8°C overnight and then registered the next day for storage and confirmatory testing.

Laboratory-based quality control

Laboratory-based quality control at KPS was conducted by systematically re-testing plasma from all samples that were positive, inconclusive or for which the initial two rapid tests were discordant using the parallel testing strategy, and from every tenth negative sample collected. The first 500 negative community samples collected in 2007 were re-tested, in view of findings from Rakai, Uganda reported early the same year. The quality control “gold standard” HIV tests comprised two parallel HIV antibody tests: the Edgware modification [18] of the Serodia® HIV-1/2 (Fujirebio Inc, Tokyo, Japan) particle agglutination test and the Vironostika® HIV Uni-Form II plus O (bioMérieux bv, Boxtel, The Netherlands) EIA test, and was performed blind to the community rapid-test results. Initial discordance in the laboratory between the Edgware and Vironostika® tests was resolved by repeating the Edgware and Vironostika® tests for that sample. Discordance between the laboratory quality control outcome and the community rapid-test results was addressed by laboratory-based repeat rapid-testing testing of first that sample, and then all samples collected on the same day for any clinical or research reason, in order to assess the likelihood of results being wrongly transcribed or of specimen mix-ups caused by mislabelling the specimens or data forms in the field or laboratory i.e. ensuring no positive samples from that day which had been reported negative and could therefore account for a false positive result on laboratory QC. All results were reviewed, if necessary arranging a follow-up visit to the participant and, in the case of samples that could not be resolved locally, sending the sample to a reference laboratory before assigning the final HIV summary result.

External quality assurance at KPS was based on retesting a panel of six specimens, provided thrice annually by the United Kingdom National External Quality Assurance Service for Microbiology (UK NEQAS). Ministry of Health staff and national reference-laboratory personnel were also invited to observe testing practices, and retest a sample of specimens. Re-testing of finger-prick samples was not undertaken.

Statistical Analyses

We assessed the performance of the rapid tests by comparing the results of community-based parallel testing with those from laboratory-based quality control. Confidence intervals were calculated using exact methods. All analyses were conducted in STATA 9.2 software (StataCorp, College Station, Texas, USA).

Results

Between September 2007 and October 2008, a total of 11172 of 16894 eligible adults agreed to HIV testing. Of these, 10819 provided a venous blood sample for HIV testing and are included in subsequent analyses; data for 331 participants who preferred to give finger-prick samples and 22 for whom the original rapid-test results or specimen were missing, are excluded from analyses and not considered further here.

The rapid test results using the parallel strategy are shown in . Overall, 7.5% (813 of 10819) of the clients tested were HIV positive; the final outcome of all rapid tests was positive or negative; with any inconclusive initial test results resolved through applying the testing algorithm. In over 99.4% of samples (10752 of 10819) there was concordance between the Determine™ and Uni-Gold™ test result. Overall, a total of 9954 samples tested negative by Determine™, of which eight were positive with the Uni-Gold™ test result; only one remained positive after the SD Bioline tie-break was used. None of the 9954 would have been further tested after the initial Determine™ test had a serial testing strategy been used, so one HIV positive case would have been missed.

Outcome of rapid HIV testing by Determine™ test result

A total of 2911 blood samples collected were subjected to internal laboratory-based quality control; these comprised all 813 positive samples and 2098 negative samples identified by the community-based parallel testing strategy, and included 67 samples for which the initial two rapid tests were discordant. The performance of community-based rapid HIV testing is presented by rapid test strategy in , using the parallel Edgware and Vironostika® laboratory quality control tests as the gold standard. The parallel rapid testing strategy actually used gave a high sensitivity and specificity, and high positive and negative predictive values. In only four samples there was discordancy between the overall laboratory and the community HIV test result; for one of these samples the specimen was brought back to the office for testing as the participant did not wish to know their results; re-testing of all specimens collected on the same day did not reveal any specimen mix-up arising from mislabelling but it is possible that the interviewer tested the wrong specimen at the office or incorrectly transcribed the rapid test results. For the remaining three samples discordancy is more likely to have arisen as a result of sample peculiarities; there having been discordancy between the initial Determine™ and Uni-Gold™ rapid tests conducted at the household, between the initial Edgware and Vironostika® quality control tests conducted in the laboratory, and between the laboratory rapid re-tests. In terms of rapid test performance a similar outcome would have been reached had the same samples that were selected for laboratory quality-control been tested using the national serial testing strategy.

Table 1

Performance of community-based rapid HIV testing

	Laboratory quality control result			Performance % (95% confidence interval)
Rapid test result (community)	Negative	Positive	Total (%)	Sensitivity	Specificity	Positive Predictive Value	Negative Predictive Value
Parallel testing a
Negative	2095	3	2098	99. 6(98.9-99.9)	100.0(99.7–100.0)	99.9(99.3–100.0)	99.9(99.6–100.0)
Positive	1	812	813
Serial testing b
Negative	2095	4	2099	99. 5(98.7-99.9)	100.0(99.7–00.0)	99.9(99.3–100.0)	99.8(99.5–99.9)
Positive	1	811	812
Uni-Gold™ alone
Negative	2089	8	2097	99. 0(98.1-99.6)	99.7(99.3–99.9)	99.1(98.2–99.7)	99.6(99.2-99.8)
Positive	7	807	814
Determine™ alone
Negative	2043	3	2046	99. 6(98.9-99.9)	97.5(96.7–8.1)	94.5(92.8–96.0)	99.9( 99.6–100.0)
Positive	47	812	859
Inconclusive	6	0	6
Total	2096	815	2911

We estimated the cost of rapid test kits in the first survey round at just over $26,019.20, based on a per-test median international transaction price of $0.80 for Determine™ and SD Bioline, and $1.60 for Uni-Gold™ [19]; the equivalent cost under a serial testing strategy, had this been applied would have been $10,086.40. Alternatively in our setting the cost of test kits per HIV-infection diagnosed would be $32.0 under the parallel system and $12.4 under the serial test system.

Discussion

Our results provide evidence that rapid-testing conducted in a “point-of-service” community-setting by non-laboratory health personnel with adequate training, combined with a system that ensures quality control, accurately determines the presence or absence of antibodies to HIV. At the level of the individual tests discordance rate between Determine™ and Uni-Gold™ was low; when used together in a parallel or serial strategy, with SD Bioline as a tie-breaker test, we have found that in this setting, the positive predictive value of the rapid tests (whether in a parallel or serial strategy) when compared to the parallel Edgware and Vironostika® laboratory testing strategy as gold standard is high. We are confident that a result in the community can be reported to the client, and that there is no need to discriminate between light and dark bands, which is difficult to do objectively and therefore has practical limitations.

In our study population there has been no indication of the problems with rapid test performance with Determine™ and Uni-Gold™ that had been observed elsewhere. The reasons for this are unclear; the performance of rapid tests for HIV antibody might be affected by early or acute HIV infection, during the period preceding the emergence of antibody, but it is unlikely this could have played a major role when incidence is substantially less than 1% per year. Variation in the test accuracy between different HIV subtypes (such as the dominant HIV-1 subtype C in Malawi, compared with subtypes A and D, and AD recombinants found in Uganda) and in the potential for cross-reactions with a different spectrum of endemic infections may in part be responsible [5]. However a more likely explanation for general variation in rapid test performance in different African settings, may relate to transport and storage of test kits and specimens and conditions under which the rapid tests were performed. In Malawi, rapid test kits were used for home-based whole blood HIV testing, contributing to optimal conditions for the collection, labelling and testing of specimens and confirmation of results; the use of whole blood from a venous specimen rather than a direct finger-prick guaranteed the required volume of whole blood. There is little in the literature comparing finger prick with whole blood for HIV rapid testing in situations of service delivery, however it would seem prudent to ensure adequate attention is paid to training staff in the optimal performance of finger pricks with correct lancets to ensure adequate volumes of blood. The performance of CD4 T-cell counts has been demonstrated to be reproducible when done in this way [20]. We did not incorporate a direct comparison of finger prick versus venous blood as this was not the primary purpose of this study, but subsequent work will need to consider this. In contrast, situations involving the transportation of the clients’ specimens away from the point of specimen collection can increase the opportunity for mislabelling of specimens, and where the testing process relies on the prior preparation of laboratory serum samples under field conditions, this may also affect the technical performance of the rapid tests used. Overall, given appropriate attention to the detail of storing and transporting of test kits, which are reasonably robust and temperature stable, and to the collection and testing of an appropriate volume of blood, we feel it likely that our results can be reproduced in service settings.

Our consideration of the performance of home-based community-testing under a serial testing strategy indicates that one participant out of the 10819 specimens tested would have been given a different result had the parallel testing strategy been used. While we found that in our population a parallel testing strategy provides HIV test results with high sensitivity, specificity and predictive values; a serial testing strategy affords very nearly the same level of accuracy at approximately 40% of the test kit cost. Our study has demonstrated that rapid HIV tests perform well when used on a wide scale in the home-based community setting. The recorded prevalence in this study of 7.5% was lower than the estimated 11.6%, but this was primarily explained by refusals to test in those who already new their status to be positive from previous rounds of testing, thus lowering the measured prevalence form previous surveys [15]. The high sensitivity of Determine™ and high specificity of Uni-Gold™ make them very well suited as screening and confirmatory tests respectively; when combined in series, with a system that ensures the appropriate storage of test devices and reagents, adherence to protocol when conducting rapid tests, and regular supervision of operator procedures to ensure that sample mix-ups and the potential reporting of wrong results do not occur, face-to-face rapid testing by government trained staff at the clients’ home can be of high accuracy. Laboratory based quality-control of field results should also be an essential component of home based testing, as it should of any system that is relying on remotely performed rapid HIV tests. This helps to ensure the quality of the tests by direct confirmation of accuracy and also by the indirect effects of ensuring operators are subjected to supervision of their testing accuracy and are motivated by this. The intensity of laboratory quality control in routine practice is not immediately obvious from our results. Our approach of all positives and a random selection of similar numbers of field test negatives is probably unnecessarily intense. The actual numbers of quality control tests may be less important in a public health based testing initiative than ensuring random sampling and feedback is done on a regular basis and on random samples to ensure that counsellors can be confident that this process is on-going and helpful.

As an initiative to increase access to and uptake of “point-of-service” HIV testing and consequent referral for appropriate care, we can be reassured that home-based counselling and rapid HIV testing is acceptable to both counsellors and their clients in the community setting.

Acknowledgements

This paper was written by AMM, RN, EB, JS, BN, JRG, ACC, NF. AMM prepared the manuscript, did statistical analysis and with NF was responsible for the scientific leadership and management of the study in Malawi. RN was responsible for laboratory assays and quality control. EB and BN supervised the field work and data collection. JS was responsible for data management and with ACC provided key input into design and implementation of data systems for laboratory testing in Malawi. JRG and NF obtained funding for the study, and with ACC provided critical comment on the manuscript. We thank all the people living in Chilumba and the surrounding area who participated in the study; we also thank the Traditional Authority Wasambo and his village headmen for their support of the study, and KPS field, laboratory, data-office, administrative and support staff for their work. Funding for this study was provided by the Wellcome Trust, United Kingdom.

Funding: Funding for this study was provided by the Wellcome Trust, United Kingdom.

Footnotes

Conflicts of interest: None

Conflict of interest. All the authors confirm that they have no conflict of interest.

Ethical considerations. This study was conducted in full accordance with ethical principles. Blood samples were obtained by venepuncture or fingerprick. Data and blood samples were obtained with the voluntary informed consent of the subjects, and ethical approval for this study was given by the Malawi National Health Sciences Research Committee (protocol number 419), and the ethics committee of the London School of Hygiene and Tropical Medicine (protocol number 5081).

References

1. Plate DK. Evaluation and implementation of rapid HIV tests: the experience in 11 African countries. AIDS Res Hum Retroviruses. 2007;23:1491–1498. [PubMed] [Google Scholar]2. World Health Organisation . Rapid HIV tests: guidelines for use in HIV testing and counselling services in resource-constrained settings. WHO; Geneva (Switzerland): 2004. [Google Scholar]3. Everett DB, Baisley K, Changalucha J, Vallely A, Watson-Jones D, et al. Suitability of simple human immunodeficiency virus rapid tests in clinical trials in community-based clinic settings. J Clin Microbiol. 2009;47:1058–1062. [PMC free article] [PubMed] [Google Scholar]4. Mayhood MK, Afwamba IA, Odhiambo CO, Ndanu E, Thielman NM, et al. Validation, performance under field conditions, and cost-effectiveness of Capillus HIV-1/HIV-2 and determine HIV-1/2 rapid human immunodeficiency virus antibody assays using sequential and parallel testing algorithms in Tanzania. J Clin Microbiol. 2008;46:3946–3951. [PMC free article] [PubMed] [Google Scholar]5. Gray RH, Makumbi F, Serwadda D, Lutalo T, Nalugoda F, et al. Limitations of rapid HIV-1 tests during screening for trials in Uganda: diagnostic test accuracy study. BMJ. 2007;335:188. [PMC free article] [PubMed] [Google Scholar]6. Government of Malawi . Guidelines for HIV Testing and Counselling (HTC) 3rd edition Ministry of Health; Lilongwe (Malawi): 2009. [Google Scholar]7. Granich RM, Gilks CF, Dye C, De Cock KM, Williams BG. Universal voluntary HIV testing with immediate antiretroviral therapy as a strategy for elimination of HIV transmission: a mathematical model. Lancet. 2009;373:48–57. [PubMed] [Google Scholar]8. Helleringer S, Kohler HP, Frimpong JA, Mkandawire J. Increasing uptake of HIV testing and counseling among the poorest in sub-Saharan countries through home-based service provision. J Acquir Immune Defic Syndr. 2009;51:185–193. [PMC free article] [PubMed] [Google Scholar]9. Menzies N, Abang B, Wanyenze R, Nuwaha F, Mugisha B, et al. The costs and effectiveness of four HIV counseling and testing strategies in Uganda. AIDS. 2009;23:395–401. [PubMed] [Google Scholar]10. Bateganya MH, Abdulwadud OA, Kiene SM. Home-based HIV voluntary counseling and testing in developing countries. Cochrane Database Syst Rev. 2007 CD006493. [PubMed] [Google Scholar]11. Ganguli I, Bassett IV, Dong KL, Walensky RP. Home testing for HIV infection in resource-limited settings. Curr HIV/AIDS Rep. 2009;6:217–223. [PMC free article] [PubMed] [Google Scholar]12. Negin J, Wariero J, Mutuo P, Jan S, Pronyk P. Feasibility, acceptability and cost of home-based HIV testing in rural Kenya. Trop Med Int Health. 2009;14:849–855. [PubMed] [Google Scholar]13. Colombet I, Saguez C, Sanson-Le Pors MJ, Coudert B, Chatellier G, et al. Diagnosis of tetanus immunization status: multicenter assessment of a rapid biological test. Clin Diagn Lab Immunol. 2005;12:1057–1062. [PMC free article] [PubMed] [Google Scholar]14. Jahn A, Floyd S, Crampin AC, Mwaungulu F, Mvula H, et al. Population-level effect of HIV on adult mortality and early evidence of reversal after introduction of antiretroviral therapy in Malawi. Lancet. 2008;371:1603–1611. [PMC free article] [PubMed] [Google Scholar]15. McGrath N, Kranzer K, Saul J, Crampin AC, Malema S, et al. Estimating the need for antiretroviral treatment and an assessment of a simplified HIV/AIDS case definition in rural Malawi. AIDS. 2007;21(Suppl 6):S105–113. [PMC free article] [PubMed] [Google Scholar]16. World Health Organisation . HIV assays: operational characteristics. Report 12: simple/rapid tests, whole blood specimens. WHO; Geneva (Switzerland): 2002. [Google Scholar]17. World Health Organisation . HIV assays: operational characteristics. Report 14: simple/rapid tests. WHO; Geneva (Switzerland): 2004. [Google Scholar]18. Sterne JA, Turner AC, Fine PE, Parry JV, Lucas SB, et al. Testing for antibody to human immunodeficiency virus type 1 in a population in which mycobacterial diseases are endemic. J Infect Dis. 1995;172:543–546. [PubMed] [Google Scholar]19. World Health Organisation . Transaction prices for antiretroviral medicines and HIV diagnostics from 2008 to October 2009. Summary Report from the Global Price Reporting Mechanism November 2009. WHO; Geneva (Switzerland): 2009. [Google Scholar]20. MacLennan CA, van Oosterhout JJ, White SA, Drayson MT, Zijlstra EE, et al. Finger-prick blood samples can be used interchangeably with venous samples for CD4 cell counting indicating their potential for use in CD4 rapid tests. AIDS. 2007;21:1643–1645. [PMC free article] [PubMed] [Google Scholar]

The evaluation of accuracy of serial rapid HIV test algorithm in the diagnosis of HIV antibodies among pregnant women in south east Nigeria | BMC Research Notes

It has been estimated that sub-Sahara Africa contributes 22.4 million of the 32.4 million cases of HIV infection worldwide [1]. This represents 67 % of HIV infection. More worrisome is the fact that HIV in this region is wearing a woman’s face with 61 % of HIV infections in this region occurring in women [1]. This has a detrimental implication for mother to child transmission of HIV infection. Overall, it has been estimated that 60 million people have been infected with HIV since the beginning of the epidemic and 25 million people have died of HIV-related causes [2].

Nigeria’s HIV infection is peculiar because of the country’s population. It has been estimated that Nigeria has one of the highest number of people living with HIV infection [3]. The annual HIV exposed births in Nigeria in 2009 was 56,681 [4]. More than 90 % of paediatrics HIV infections are as a result of mother to child transmission [5]. Diagnosis is also more challenging because of presence of HIV-2 in the region.

HIV prevention and treatment hinges on the availability of accurate and feasible diagnostic tests. HIV counseling and testing is the gateway for HIV prevention, care, treatment and support of interventions. Among pregnant women, screening has proven to be more effective than risk-based approach for detecting unsuspecting maternal HIV infection [6]. Screening for HIV infections were previously done using conventional ELISA and confirmed with western blot testing until the evolution rapid HIV testing kits. Both parallel and serial rapid test algorithm has been used for screening and diagnosis of HIV infection in Nigeria.

The routine use of conventional ELISA was abandoned because it is technically demanding, and requires sophisticated, regularly maintained equipment and constant supply of electricity. The ELISA kits use both natural and recombinant antigens. They are updated continuously to increase their sensitivity to newly discovered species like group O viruses [7]. The fourth generation ELISA also detects the presence of p24 antigen thereby improving the sensitivity.

Rapid tests for the detection of antibodies to HIV have revolutionized the diagnosis and management of patients with HIV infection. It allows timely point of care, provision of results and do not require the laboratory facilities needed for conventional ELISA and western blot testing [8–11]. Rapid HIV tests have been widely used for voluntary HIV counseling and testing, antenatal surveillance, and population screening [10, 11]. These tests are simple to use and cheaper than laboratory based HIV antibody tests [12]. Introduction of rapid HIV tests has contributed in the scaling up of HIV-testing programme and enabled diagnosis of HIV in persons who might not have had their infections diagnosed otherwise [13–17]. This is more pertinent in sub-Sahara Africa with very high disease burden and weak health sector.

The sensitivity of many rapid test kits is comparable to the conventional enzyme immunoassays [15–18]. Eller et al. reported a sensitivity of 98.6 % and specificity of 99 % in Uganda [16]. This agrees with the result of several studies [18–20]. These results met the WHO criteria of 98 % sensitivity and 99 % specificity. Rapid HIV tests have been developed for on-site real time testing and quality of testing is dependent on user and test kits. High false positive rates have been observed with some test kits [21–25].

Studies have reported poor positive predictive value of three rapid tests if weak bands are interpreted as positive according to manufacturers’ recommendation [23, 26]. It has been postulated that weak positive bands may reflect cross-reactions with other infections [23].

Various HIV testing algorithms were introduced to improve the accuracy of testing. These testing algorithms involve a combination of tests used either in sequence or parallel, designed to achieve predictive values close to 100 %. These include the parallel testing and serial testing. Parallel screening is the use of two tests simultaneously, each test being a check on the other, and can be considered to create efficiency. Serial testing involve the use of rapid test kit with sensitivity close to 100 %. Second test is done only if the initial test is positive. The parallel approach is expensive and in lower prevalence settings, may lead to the use of longer numbers of tests than the use of a serial strategy. Currently serial rapid testing is the option in Nigeria based WHO recommendation.

Despite the improvement to access and wide scale implementation, quality assurance mechanism is very important to validate the accuracy as stated by the manufacturers. In addition, it will also detect post market problems like batch variations, storage problems and fake products.

High false positive rates have an adverse effect on the health system and individuals. The individuals will suffer stigma and discrimination, with attendant psychological and social consequences. She may also be prone to domestic violence and exposed to the unnecessary and potentially toxic medical treatment. This will lead to increase in antiretroviral drugs budget and will put a heavy strain on the health sector especially in developing countries. In addition, a HIV negative person will be meant to live with the stigma associated with the disease with attendant psychological and social consequences. False negative results have a great implication for mother to child transmission of HIV infection. These women are denied the benefit of antiretroviral therapy in reduction of mother to child transmission.

Studies have shown reduced ability of rapid test kits in detecting some strains of HIV-1 and HIV-2 antibodies when compared with conventional ELISA [26–29]. More worrisome is the observation that some rapid test kits used in different algorithm detect the same type of antigens contrary to WHO recommendations [30].

Rapid point of care HIV tests has created new challenges and opportunities for service providers, policy makers and researchers concerning broad scale identification of HIV seropositive persons. The major challenge is to identify most suitable assays for a given circumstance without compromising the test results. It is essential to establish quality assurance programs so that benefits of rapid point of care HIV test will be optimized. This will help to detect batch to batch differences, storage and other post market problems that may hinder the accuracy of the test kits.

Periodic evaluations of these kits will help in making sure that the kits meet the minimum standard. This study evaluated the accuracy of the serial rapid test algorithm by determining the sensitivity, specificity, negative and positive predictive values of the serial rapid HIV test algorithm among booked antenatal women in Nnewi, South East Nigeria, which is one of the centres of excellence for prevention of mother to child transmission of HIV infection in Nigeria.

Accuracy of Re-Reading HIV Rapid Tests and the Effect of Prolonged High Temperature

Background: Accurate rapid diagnostic test (RDT) results are critical to HIV testing, care and prevention services. However, suboptimal storage at ambient temperatures above manufacturer-recommendation is common in sub-Saharan Africa. Re-reading of used test kits can provide valuable programmatic quality-assurance, and “late” reading is also commonly reported following HIV self-testing. We evaluated the effects of prolonged exposure to high temperatures on both initial accuracy, and reproducibility of late reads.

Methods: A cross-sectional diagnostic evaluation in Blantyre, Malawi. Consenting participants attending HIV testing services had parallel testing with 3 RDTs (OraQuick (oral), Determine 1/2™, Alere, Waltham, USA and Uni-Gold™ Recombigen^® HIV, Trinity Biotech, Bray, Ireland): a) preincubated for 28 days at 37 ^s‹C as intact packages and b) the same 3 RDTs stored under optimal conditions (6 tests in total). All 6 kits were read by the study nurse at the recommended time, and then again by a laboratory technician on the same day and monthly for 12 months (although with reference to previous results). Optimally stored Uni-Gold/Determine/SD Bioline were used for the gold standard.

Results: Of 378 participants, 198 (53.4%) were male with median age 31 years (IQR 25-40). Compared to gold standard, sensitivity for normal and high temperature OraQuick, Determine and Uni-Gold are shown in the table below. All but 6 participants had concordant results from each of the 6 kits, with no discernable effect on accuracy from preincubation. One participant was positive on both OraQuick (optimal) and Determine (optimal), but negative on the other RDTs, and was classified as HIV-negative. A further 5 participants had false-negative results on one or more RDTs. Notably, 108 (28.6%) reported being on antiretroviral treatment (ART). Over 12 months of re-reading used OraQuick kits; 1 (0.3%) in both optimal-stored and high temperature groups changed from negative to positive (different clients). In both cases participants were known to be on ART.

Conclusions: This study showed that rapid diagnostic HIV test kits stored at prolonged high temperature did not appreciably affect diagnostic performance. Repeated reading of OraQuick kits up to 12 months after testing appears to be highly reproducible, although not recommended by the manufacturer. Clients seeking retesting while on ART maybe an increasing common cause of inaccuracy in HTC clinics.

Accuracy Evaluation of Diagnostic HIV Rapid Tests with Oral Fluid and Whole Blood in Hard to Reach High-risk Groups

World Health Organization (WHO). Global Health Observatory (GHO) data: HIV/AIDS. Geneva: World Health Organization; 2017.

The Joint United Nations Programme on HIV/AIDS (UNAIDS). 90-90-90: an ambitious treatment target to help end the AIDS epidemic. Geneva: The Joint United Nations Programme on HIV/AIDS; 2014.

World Health Organization (WHO). HIV/AIDS topical information: HIV testing services. Geneva: World Health Organization; 2017.

Cherutich P, Bunnell R, Mermin J. HIV testing: current practice and future directions. Current HIV/AIDS Reports. 2013;10(2):134-41.

Thailand National AIDS Committee. National strategic information and monitoring and evaluation plan for HIV/AIDS Thailand 2012 to 2016. Bangkok: Thailand National AIDS Committee; 2013.

US Food and Drug Administration. OraQuick® In-home HIV test summary of safety and effectiveness. Silver Spring, MD: US Food and Drug Administration; 2012.

CLIA database. CLIA record BP010047. Rockville, MD: US Food and Drug Administration; 2008.

Wesolowski LG, MacKellar DA, Facente SN, Dowling T, Ethridge SF, Zhu JH, et al. Post-marketing surveillance of OraQuick whole blood and oral fluid rapid HIV testing. AIDS. 2006;20(12): 1661-6.

Pant Pai N, Joshi R, Dogra S, Taksande B, Kalantri SP, Pai M, et al. Evaluation of diagnostic accuracy, feasibility and client preference for rapid oral-based diagnosis of HIV infection in rural India. PLoS One. 2007;2(4):e367.

Pai NP, Barick R, Tulsky JP, Shivkumar PV, Cohan D, Kalantri S, et al. Impact of round-the-clock , rapid oral fluid HIV testing of women in labor in rural India. PLoS Med 2008;5(5):e92.

Hutchinson AB, Branson BM, Kim A, Farmham PG. A meta-analysis of the effectiveness of alternative HIV counseling and testing methods to increase knowledge of HIV status. AIDS. 2006;20(12):1597-604.

Thailand Food and Drug Administration. Medical device control in Thailand. Nonthaburi: Thailand Food and Drug Administration; 1990.

Department of Medical Sciences, Thailand Ministry of Public Health. Diagnostic HIV tests available in Thailand. Nonthaburi: Department of Medical Sciences; 2014.

MedCalc. Diagnostic test evaluation calculator [Internet]. Ostend: MedCalc Software bvba; 2015 [cited 2015 Jul 31]. Available from: https://www.medcalc.org/calc/diagnostic_test.php.

Lowry R. Vassarstats: statistical computation – McNemar’s Test [Internet]. [Place unknown]: Vas-sarstats; 2015 [cited 2015 Jul 31]. Available from: http://vassarstats.net/propcorr.html.

Sarstats. 2015 [cited 2015 Jul 31]. Available from: http://vassarstats.net/propcorr.html.

O’Connell RJ, Merritt TM, Malia JA, VanCott TC, Dolan MJ, Zahwa H, et al. Performance of the OraQuick rapid antibody test of diagnosis of human immuno- deficiency virus type 1 infection in patients with various levels of exposure to highly active antiretroviral therapy. J Clin Microbiol. 2003;41(5):2153-5.

Choko AT, MacPherson P, Webb EL, Willey BA, Feasy H, Sambakunsi R, et al. Uptake, accuracy, safety, and linkage into care over two years of promoting annual self-testing for HIV in Blantyre, Malawi: a community-based prospective study. PLoS Med. 2015;12(9):e1001873.

Mavedzenge SN, Sibanda E, Mavengere Y, Hatzold K, Mugurungi O, Ncube G, et al. Supervised HIV self-testing to inform implementation and scale up of self-testing in Zimbabwe. J Int AIDS Soc 2015;18(Suppl 4):96.

Stekler JD, O’Neal JD, Lane A, Swanson F, Maenza J, Stevens CE, et al. Relative accuracy of serum, whole blood and oral fluid HIV tests among Seattle men who have sex with men. J Clin Virol 2013;58(Suppl 1):e19-22.

Suntharasamai P, Martin M, Choopanya K, Vanichseni S, Sangkum U, Tararut P, et al. Assessment of oral fluid HIV test performance in an HIV pre-exposure prophylaxis trial in Bangkok, Thailand. PLoS One 2015; 10(12): e0145859.

McNeil Jr DG. Rapid H.I.V. home test wins federal approval. The New York Times 2012 Jul 3: A1.

Facente SN, Dowling T, Vittinghoff E, Sykes DL, Colfax GN. False positive rate of rapid oral fluid HIV tests increases as kits near expiration date. PLoS One. 2009;4(12):e8217.

Delaney KP, Branson BM, Uniyal A, Phillips S, Candal D, Owen SM, et al. Evaluation of the per-formance characteristics of 6 rapid HIV antibody tests. Clin Infect Dis 2011;52(2):257-63.

Pant Pai N, Balram B, Shivkuma S, Martinez-Cajas JL, Claessens C, Lambert G, et al. Head-to-head comparison of accuracy of a rapid point-of-care HIV test with oral versus whole-blood specimens; a systematic review and meta-analysis. Lancet Infect Dis 2012; 12(5): 373-80.

Pavie J, Ruchline A, Loze B, Niedbalski L, Delaugerre C, Laforgerie E, et al. Sensitivity of five rapid HIV tests on oral fluid or finger-stick whole blood: a real-time comparison in a healthcare setting. PLoS One 2010; 5(7):e11581.

Centers for Disease Control and Prevention (CDC). False-positive oral fluid rapid HIV tests–New York City, 2005-2008. MMWR Morb Mortal Wkly Rep 2008;57:660-5.

Stekler JD, Swenson PD, Coombs RW, Dragavon J, Thomus KK, Brenan CA, et al. HIV testing in a high-incidence population: is antibody testing alone good enough?. Clin Infect Dis 2009;49(3):444-53.

What You Need to Know About Getting Tested for HIV

Screening tests for HIV look for either HIV antibodies (proteins your body makes to fight the virus), or both antibodies and antigens (substances found on the viruses that trigger the production of antibodies).

Most laboratories now use what are known as fourth-generation combination antigen-antibody tests, and there is also a rapid antigen-antibody test. This test detects the antigen p24, which the body produces before HIV antibodies develop.

According to the HIV.gov, most people make enough antigens and antibodies for these combination tests to detect HIV in two to six weeks (13 to 42 days) after infection. (3)

In the past, the enzyme-linked immunosorbent assay (ELISA), an antibody-only test, was a commonly used screening test for HIV, followed by a confirmatory test for antibodies in the case of a positive result. It’s nearly 100 percent accurate in diagnosing chronic HIV, but it is not as sensitive when it comes to acute (or very early) infection, when the body hasn’t yet produced enough antibodies in response to the presence of HIV. (4)

The ELISA test is often referred to as a third-generation antibody test.

Antibody-only tests still make up most of the rapid tests and at-home tests that are available, which are performed on blood or oral fluid (cheek swabs).

A rapid antibody screening test provides results within a half an hour.

The CDC notes that these tests are used in clinical and nonclinical settings, usually with blood from a finger prick or with oral fluid. (1)

An at-home oral fluid antibody self-test also provides results quickly. You have to swab your own mouth to collect an oral fluid sample and use a kit to test it. Results are available in 20 minutes.

An at-home collection kit uses a blood sample collected by pricking your finger. You then send it to a lab for results, which are sometimes available the next day.

It can take 23 to 90 days for an antibody test to detect HIV infection after exposure, though tests that use blood drawn from a vein rather than from a finger prick, or tests done on oral fluid, can typically detect the infection sooner. (1)

HIV screening tests are very accurate, but they are not 100 percent. Follow-up blood tests are necessary to confirm a positive HIV diagnosis. If you have a positive result after using an antibody test, you’ll need to confirm those results with follow-up testing.

90,000 Rapid HIV tests. Can trust?

Rapid HIV tests. Can trust?

According to statistics, 30% of the total number of HIV patients in our country do not even know that they have this disease. And this means that they are very at risk of starting the disease and transferring it to AIDS. But besides this, they put the people around them at risk, which means: the disease spreads, and everyone can get sick.

How can this be avoided? It’s very simple – you need to test for HIV at least once a year. To do this, in each city there are specialized centers, where everyone can be examined and be confident in their status. But sometimes there are situations when it is not possible to quickly undergo full medical testing. For such situations, they came up with an excellent solution – rapid HIV tests. With the development of technology, they are becoming more accurate and in many ways are not inferior to laboratory testing.Every year there are more and more of them, the choice becomes more and more diverse. In order to guide you in this variety, we will try to tell you the main points about express tests.

To begin with, there are 3 types of rapid tests:

• based on saliva;
• by urine sample;
• on a blood sample.

The most popular rapid test is the saliva sample test.This is not surprising, because it is the easiest to use and does not require complex manipulations or skin damage. In addition, this test minimizes the possibility of HIV transmission. It is a device that can only be used once. To determine the presence of the human immunodeficiency virus, it is necessary to collect the pericardial fluid – saliva. The result will be ready in 20 minutes. The test determines the presence of HIV types 1 and 2 in the body. The accuracy of the test is quite high, according to some sources it is close to 99%.However, according to experts, if the test is positive, there is no need to sound the alarm and make a final diagnosis. In any case, for an accurate result, it is necessary to undergo an examination in a specialized institution.

The rapid test, which uses a urine sample to determine HIV, is less popular and is more of an adjunct test than a primary test. It is very similar in form to a pregnancy test. You need to collect the urine in a jar and dip the strip into it.The result will be ready in 10-20 minutes.

And, finally, one of the most accurate, but the most “dangerous”, express tests – based on a blood sample. To determine HIV in the body, it is necessary to take blood from a finger and lower it into the device. The complexity of this test, on the one hand, is that it is necessary to break the skin, and this means create an additional risk of infection, on the other hand, the virus in the blood from a finger can be stored for no more than 2-3 minutes, so the material must be used immediately to determine the test results …

Rapid tests can also be performed at home if there are serious reasons for this. It must be remembered that in order to increase the accuracy of testing, you need to observe precautions and disinfection, strictly follow the instructions. Well, if you read this instruction in full, you can see there information that in order to confirm the results of express tests, you need to be re-tested in a specialized center or in a polyclinic. Do not forget about this in order to have a 100% result and be confident in your status.

90,000 WHO / Europe | Rapid HIV testing saves lives: it’s time to switch to rapid tests

Association “Youth for the Right to Live”, Balti, Moldova

Today, WHO issued a strong recommendation for HIV testing, urging countries to stop using the slower and less accurate testing methods such as Western blotting and linear immunoassay, replacing them with the simpler rapid testing method.

It is essential that people living with HIV who are unaware of their diagnosis get tested and receive antiretroviral therapy (ART) promptly. ART prevents HIV infection from progressing to AIDS; when, after starting therapy, the level of the virus in the blood becomes so low that it is not detected on a blood test, people can live with HIV without passing it on to others.

Dr Masoud Dara, Coordinator for Communicable Diseases at WHO / Europe, said: “Rapid testing saves lives by making HIV testing more affordable and reducing the waiting time for test results.When such testing is performed outside a health facility by individuals who care for their clients and are attentive to their needs, people are more likely to use testing services. If the test is positive, treatment should be started immediately; if the test result is negative, then this is a good reason to inform the client about ways to prevent HIV infection, such as taking pre-exposure prophylaxis drugs and using condoms.Whatever the analysis, it is with the testing phase that assistance begins. ”

New testing methods contribute to faster and more accurate results

The recommendation published today is based on a thorough analysis of the most recent data and a systematic review of existing practice that was carried out by WHO in

In the review, immunoblot and linear immunoassay testing strategies for confirming a diagnosis of HIV infection were compared with strategies based on rapid diagnostic testing, which can be performed at the point of care, in combination with an enzyme-linked immunosorbent assay.The experts concluded that the use of rapid tests in combination with the enzyme-linked immunosorbent assay is generally a faster, more accurate and less costly method for diagnosing HIV infection. The analysis is summarized in the policy brief; the publication of the global recommendations will be timed to coincide with World AIDS Day on 1 December.

Late diagnosis can lead to death

Late diagnosis of HIV infection remains a problem in most countries in the WHO European Region: it is estimated that only 82% of people living with HIV in the Region know about your status.If you look at the situation in the countries of Eastern Europe, then only 74% of people living with HIV know about their status. Therefore, this recommendation is especially relevant for the European Region.

A late stage of infection is observed in every second newly diagnosed patient with a confirmed diagnosis of HIV infection. It can take several weeks to confirm the diagnosis using immunoblotting and linear immunoassay techniques, resulting in delayed initiation of life-saving ART.Many patients do not come to the clinic for a second visit to confirm the test results. The consequence is an increase in the number of AIDS cases and related deaths that could have been avoided by starting treatment earlier.

However, with new technologies providing fast confirmation of results, HIV testing is now easier than ever. Moreover, in many European countries there is an institution of peer-to-peer consultants who are not necessarily health professionals, but who have received special training and provide advice and support, and can also conduct testing outside medical institution and inform the client of the result in a matter of minutes.

Unfortunately, very few countries have adopted the latest in HIV testing. Often, the delay in their implementation is due to factors such as legal barriers or unwillingness to discuss changes in public procurement plans and specifications of laboratory equipment.

WHO / Europe encourages countries in the Region to join the European Testing Week initiative. European Testing Week is a biannual, region-wide campaign calling on organizations to make every possible effort to reach as many people as possible with testing for one week in May and one week in November.The main objective of the campaign is to promote early detection of HIV and hepatitis, raise public awareness of these diseases and expand access to testing services and, if necessary, to further medical care. The campaign is held from 22 to 29 November 2019

GOAUZ “MOCSVMP” – Testing

TESTING

How is HIV diagnosis carried out? All about preparation and interpretation of research results
HIV testing. Who should get tested and when?
What tests detect HIV
“WINDOW PERIOD”
Rapid HIV tests. Can you trust them?

How is HIV diagnosis carried out?

All about the preparation and interpretation of research results

HIV testing is a simple and painless procedure. How it goes, whether it is necessary to prepare, what the test results show.

Free will

HIV testing in most cases is voluntary, therefore, it is carried out only after obtaining the patient’s informed consent.

How to take the test

Blood is taken for analysis in the treatment room. Blood is taken from the cubital vein in an amount of 3-5 ml into a sterile test tube. Blood can be taken both in the morning on an empty stomach and at any time of the day after a meal.

Risk of HIV infection during examination

In medical institutions, only disposable instruments are used, or they undergo high-quality sterilization. It is not possible to become infected with HIV by donating blood.

Types of test results

The results of the primary diagnosis of HIV are of three types – positive, negative and doubtful.

If positive

A positive result means that the test system has detected antibodies to HIV in the blood sample, this may indicate that you really have HIV infection.A positive result in ELISA must be confirmed in an immune blot with the same blood sample. In rare cases, the result is false positive. False positive results occur with viral infections in pregnant women, and with autoimmune diseases. A positive result may also be referred to as seropositive or HIV + status.

If negative

A negative result indicates that no antibodies to HIV are found in the blood – that is, there is no HIV infection.Or that HIV infection has occurred recently and the amount of antibodies is below the threshold values ​​determined by the test system, that is, the “window” period lasts. If there has recently been a dangerous situation regarding HIV infection, then it is advisable to repeat the examination after three months and six months. A negative result is also called seronegative, or HIV.

If the result is doubtful

It is quite rare that test results are questionable. This can be in two cases: when a person has recently become infected with HIV and the concentration of antibodies is insufficient for detection with conventional test systems, or when HIV is absent, but there are other chronic diseases – metabolic or autoimmune in nature.Therefore, testing immediately after a hazardous contact is impractical. If a questionable result was obtained with an enzyme immunoassay, a confirmatory analysis is usually performed using an immunoblot. If the dubious result persists, the examination is repeated after 1-3 months and the patient is observed for six months.

HIV testing.

Who should get tested and when?

HIV testing is usually a strictly voluntary procedure.However, there are circumstances when it is simply necessary to be tested for HIV infection.

In the eyes of society, HIV testing still looks unusual and even strange. Perhaps your friends and family, having learned about your plans to be tested, will suspect you of “bad” behavior. But in vain. Because HIV testing is, first of all, a sign of taking care of your health.

Optional examination

HIV testing is voluntary in most cases.There are times when HIV testing is mandatory.

Sexual activity

Anyone who is sexually active should be tested for HIV. It is optimal to find out the HIV status of a partner even before entering into an intimate relationship with him. If this could not be done, then it is necessary to be tested for HIV infection 3 months after the onset of sexual activity. The same applies to the situation of changing a sexual partner. If for a long time the sexual partner is always constant, then there is no need for periodic testing for HIV.

Post-hazard screening

In a situation of casual sexual contact with a partner whose HIV status is unknown, informative determination of antibodies to HIV in the blood is possible only after three months. The first three months after HIV infection lasts a period of “window” when antibodies to the virus are just beginning to be produced and their level is below the threshold value determined by test systems.

A similar situation – if there is suspicion of infection through blood, for example, when injecting drugs with a non-sterile syringe.After dangerous, from the point of view of HIV infection, situations with negative results of the first examination, it is advisable to take repeated tests every three months during the year.

If there are signs of illness

Sometimes a blood test for HIV is necessary for clinical signs – for example, if a person has severe immunodeficiency or there are clinical signs that suggest HIV infection or AIDS. An examination is also recommended when detecting sexually transmitted diseases, hepatitis B or C, tuberculosis.

Representatives of certain professions

Representatives of a number of professions who, during their work, are in direct contact with blood and body fluids – doctors, laboratory assistants, nurses – should have a blood test for HIV infection annually. In addition, medical workers of AIDS centers who are in constant contact with HIV-positive people need to be examined.

Contacts with HIV-positive people

Testing is especially important for people in contact with HIV-infected people, including at home.People who have regular sex with an HIV-infected person should be tested every three months, even if they use a condom all the time.

After blood transfusion and transplantation

Patients who have received blood components (especially erythrocyte mass) should be tested for HIV after three months. The same applies to those to whom donor organs and tissues have been transplanted.

Examination of pregnant women

Pregnant women also need to be tested for HIV in the early stages – when contacting an antenatal clinic.If the result is negative, testing is repeated in the third trimester of pregnancy to exclude the “window” period.

Survey of children born to HIV-positive women

With regard to children born to HIV-infected women, it is not advisable to carry out a blood test for HIV antibodies during the first 12-18 months. The fact is that during pregnancy, maternal antibodies to HIV are transferred with the blood to the fetus and remain in the child’s blood for up to 18 months, even in the absence of HIV infection.Thus, newborns either undergo PCR diagnostics of HIV, or after 18 months – an analysis for antibodies to HIV.

Examination of representatives of risk groups for HIV infection

People at risk of HIV infection – homosexuals and commercial sex workers – should be tested for HIV every three months, regardless of whether they use a condom during sexual intercourse. Drug users also need to be screened regularly, every three months, including those who use non-injecting drugs.

Re-examination

Repeated and further tests for HIV infection are determined by a specialist based on the results of the initial examination, clinical data and depending on the situation.

What tests detect HIV

According to Federal Law No. 38-FZ “On Preventing the Spread of Disease Caused by Human Immunodeficiency Virus (HIV Infection) in the Russian Federation”, every citizen of the Russian Federation has the right to undergo voluntary anonymous testing to determine their HIV status.

There are several different tests, according to the results of which it is possible to understand for sure whether there is a virus in the body or not, and questions about testing are probably the most relevant not only for HIV-positive people, but also for those who do tests for the sake of prevention.

We should probably start with how the evolution of HIV tests took place. For the first time, HIV tests began to be done in 1985. At that time, the main purpose of testing was to detect infection in donated blood. Since there was no cure for HIV at that time, there was no incentive to do this test either.

Later, antiretroviral drugs were developed, which became a big step in the treatment of HIV infection. Therefore, not only doctors, but also people who care about their health began to pay much more attention to testing. In total, several generations have been developed in the history of the development of HIV tests. Tests from the first to the third generation can only find antibodies in the blood. They are secreted in the blood by the immune system in response to the appearance of a foreign microorganism, in this case a virus.Most of these tests are based on an enzyme-linked immunosorbent assay (ELISA). These tests are also called “indirect testing”. The first test detected antibodies using a sonicated virus called lysate. This is the first test that could detect HIV in the body. However, he could only detect HIV1. Also, the first generation test was not very sensitive and specific, so it required improvement.

The next round of development in the study of HIV falls on the second half of the 20th century, more precisely in the 80s.Second generation tests were developed around this time. They could already detect antibodies to HIV1 and HIV2. Recombinant and / or peptide methods were used to determine the presence of antibodies. The recombinant method used genetically modified proteins that were similar to the protein antigens of the virus. The peptide method used protein fragments that were synthesized by an artificial, chemical method.

In the 90s, third generation tests appeared. Their main difference is that they have a higher sensitivity.This testing is based on a specific interaction between an antibody produced by the body and a hostile antigen of the virus.

The fourth generation test is most commonly used today. He, like previous tests, detects antibodies, but at the same time, he is still sensitive to HIV antigens. This shortens the seronegative period and gives more accurate results.

The enzyme-linked immunosorbent assay or ELISA is currently the most popular and used method.Its accuracy is about 99%. But in addition to enzyme-linked immunosorbent assay, other methods for determining HIV are often used. If ELISA is usually performed as a screening test, i.e. during the initial examination, immune blotting is used to make an accurate diagnosis of HIV. It is much more difficult to carry out, but gives a more accurate result, because it is more sensitive and specific. For IB, blood from a vein is also used, after which it undergoes a special treatment, and then is applied to a special strip of a nylon filter or nitrocellulose.A reaction occurs and the result is displayed on a strip – it becomes visible. If stripes appear in certain places of the strip, then this becomes a confirmation that the blood contains antibodies to HIV.

Another method for detecting HIV in the body is the polymerase chain reaction (PCR). However, it is much more difficult to use and requires a lot of skill. PCR analysis examines nucleic acids, and this is DNA and RNA, thus, it turns out that it determines the genetic material of a microorganism.This research method is very accurate – up to 98% – 99%. But you need high-quality reagents and highly qualified professionals who can correctly conduct research and diagnose.

These are currently the most popular HIV testing methods. As mentioned above, no test can give a result with 100% accuracy. Therefore, an additional method is always used for confirmation. Only by passing several testing methods will doctors be able to make a definitive diagnosis.What kind of testing will be carried out for the patient is also determined by the doctor, based on the individual characteristics of the organism.

“WINDOW PERIOD”

Every, or almost every person in life can have situations in which he is at risk of contracting HIV.

Unfortunately, sometimes such situations are extremely difficult to avoid, and they can arise absolutely spontaneously.

What to do if there is a suspicion, even the smallest, that you have become infected?

Of course, you need to be tested so that there is no doubt.And now, the testing is passed, the agonizing expectation of the results has passed, and you are informed that the results are negative. It would seem that you can already calm down, but the doctor tells you about some mysterious “window period”, sometimes calling this incomprehensible “window” seronegative. And the fear starts to return. To avoid this fear, we will talk about the seronegative window – we will explain what this term means, how long this period lasts, and how to behave at this time.

So, the “window period”, seronegative, seroconversion window – is the period of time when an infectious agent (virus, bacteria, etc.)) has already entered the body and multiplies, but antibodies in the patient’s blood have not yet appeared.

Currently, HIV tests do not detect the virus itself in the body. They can only determine the presence of antibodies or antigens (an antibody is a protein that the immune system produces in response to the appearance of foreign molecules in the body. Antigen is a molecular component that carries foreign genetic information).

But the body reacts differently to the appearance of the virus, and accordingly, it begins to produce antibodies in a different period – from 2 weeks to 6 months.Antigens appear in the body immediately, but their concentration may be so low that the test cannot detect them, and during this period a person will receive a negative HIV test result. So it is this period – from the moment of infection to the appearance of antibodies – that is called the “window period”.

Therefore, doctors, in order to accurately determine the presence of HIV in the body, advise doing the test several times – 2 and 6 months after the moment when a person could become infected.

It is very important to remember that even if your tests are negative and you suspect that you may have contracted HIV, you should be very careful until your final test result is available.Because the virus can live and develop in the body, be contained in the blood and secretions, and a person can be not only a carrier, but also a potential spread of the disease.

If you suspect that you may have become infected with HIV, you must understand and be aware that now you have a responsibility because you can infect people close to you.

Even if after a while it turns out that the fears were in vain, and the HIV test turned out to be negative, the precautions taken will not be superfluous.Because in this way you minimize the possibility of infection with other serious diseases. It is always important to remember about basic preventive measures that will help you stay healthy and prevent people close to you from getting sick.

Rapid HIV tests. Can you trust them?

How can you avoid this? It’s very simple – you need to test for HIV at least once a year. To do this, in each city there are specialized centers, where everyone can be examined and be confident in their status. But sometimes there are situations when it is not possible to quickly undergo full medical testing.For such situations, they came up with an excellent solution – rapid HIV tests. With the development of technology, they are becoming more accurate and in many ways are not inferior to laboratory testing. Every year there are more and more of them, the choice becomes more and more diverse. In order to guide you in this variety, we will try to tell you the main points about express tests.

To begin with, there are 3 types of express tests:

– based on saliva;

– according to the urine sample;

– based on a blood sample.

The most popular rapid test is the saliva sample test. This is not surprising, because it is the easiest to use and does not require complex manipulations or skin damage. In addition, this test minimizes the possibility of HIV transmission. It is a device that can only be used once. To determine the presence of the human immunodeficiency virus, it is necessary to collect the pericardial fluid – saliva. The result will be ready in 20 minutes. The test determines the presence of HIV types 1 and 2 in the body.The accuracy of the test is quite high, according to some sources it is close to 99%. However, according to experts, if the test is positive, there is no need to sound the alarm and make a final diagnosis. In any case, for an accurate result, it is necessary to undergo an examination in a specialized institution.

The rapid test, which uses a urine sample to determine HIV, is less popular and is a complementary test rather than a primary test. It is very similar in form to a pregnancy test.You need to collect the urine in a jar and dip the strip into it. The result will be ready in 10-20 minutes.

And, finally, one of the most accurate, but the most “dangerous”, express tests – based on a blood sample. To determine HIV in the body, it is necessary to take blood from a finger and lower it into the device. The complexity of this test, on the one hand, is that it is necessary to break the skin, and this means create an additional risk of infection, on the other hand, the virus in the blood from a finger can be stored for no more than 2-3 minutes, so the material must be used immediately to determine the test results …

Rapid tests can also be performed at home if there are serious reasons for this. It must be remembered that in order to increase the accuracy of testing, you need to observe precautions and disinfection, strictly follow the instructions. Well, if you read this instruction in full, you can see there information that in order to confirm the results of express tests, you need to be re-tested in a specialized center or in a polyclinic. Do not forget about this in order to have a 100% result and be confident in your status.

Home rapid HIV tests will now become cheaper and more affordable

Experts emphasize that self-testing is one of the most important tools in the fight against HIV / AIDS. A simple test, which can be bought at a pharmacy, allows you to quickly establish your HIV status at home. This will enable many people with HIV to learn about the disease early and seek immediate medical attention and treatment.

Experts also note that this option will help people who do not want to get tested in clinics and hospitals because they are afraid of publicity and discrimination.In many countries and communities, the phenomenon of stigmatization of AIDS patients still exists today, UNITAID recalls.

Read also INTERVIEW We train doctors to talk to HIV-infected women

“WHO welcomes this development, HIV self-test kits will now become cheaper and more people will have access to them. This news is especially relevant now as HIV self-testing has become an important option during the COVID-19 pandemic, when other options are limited, ”said WHO spokesman Meg Doherty.

The agreements reached by the management of UNITAID and Viatris will expand the production of rapid home blood tests and make them available to consumers. Until now, the market for self-diagnosis of HIV has been dominated by only one type of oral test, which is significantly more expensive.

UNITAID experts report that over the past few years, the number of people who know they are HIV-positive has increased from 45 percent to 81 percent.This has accelerated progress in the fight against HIV / AIDS and has brought the international community much closer to achieving one of the most important targets of the 2030 Agenda for Sustainable Development, according to which 90 percent of HIV-positive people should know their status.

“Self-testing for HIV is an essential factor in helping people know their status and one of the main ways to achieve the global HIV goals. This development of events [the emergence of new home tests on the market – approx.Ed.] will help countries gain access to cheap home tests, ”said UNITAID spokesman Robert Matiru.

90,000 HIV testing. Know your HIV status!

Many people think that HIV infection, if it exists, is somewhere far away, and a modern socially adapted person cannot face it. Indeed, drug users, sexual partners of HIV-infected people, women involved in sex work, and men who have sex with men are at a serious risk of becoming infected with the human immunodeficiency virus (hereinafter referred to as HIV).However, given that the main part in the structure of HIV transmission routes is currently occupied by the sexual route, no one can be insured against this infection. This means that any person engaging in sexual activity or changing sexual partners runs the risk of contracting HIV. It is impossible to become infected with HIV sexually only if in a couple both partners are not infected with HIV and both remain faithful to each other throughout the entire period of their relationship. Unfortunately, as practice shows, in most cases people in a couple not only do not know whether their partner is infected with HIV or not, but they themselves do not know about their status, since they are not tested for HIV infection.

The danger of HIV infection also lies in the fact that a person infected with HIV for a long time feels absolutely healthy. The main method of laboratory diagnosis of HIV infection is the detection of antibodies to HIV in the blood serum using enzyme-linked immunosorbent assay (ELISA). From the moment of HIV infection to the time when the ELISA method can determine the presence of antibodies to HIV in the blood, it can take from 3 to 6 months. This period is called the window period. The test for antibodies to HIV during this period will be negative, but at the same time the person can already infect other people.

General information : HIV testing in healthcare organizations.

A passport is required for the survey (except for an anonymous survey).

Step # 1. Come to a healthcare facility with a treatment room.
Step # 2. Have a short interview with a specialist from the institution.
A specialist will tell you what the analysis is and what test results are, and will also help you assess how high the risk of HIV transmission was.The consultation is anonymous.
Step 3. Blood sampling from a vein (on an empty stomach) in the treatment room of a healthcare facility (during the working day). All used instruments are sterile and disposable.
Step 4. Obtain the result from a specialist or in the treatment room of the institution.

The result was not reported by phone.

After receiving the test result, it is also worth talking to a specialist.As a rule, after the test, the result obtained and the actions that are recommended to be taken in this or that case are discussed.

An HIV test is mandatory for those who :
– at least once had unprotected sexual contact with a partner whose HIV status is unknown to him;
– experienced injecting drug use;
– got a tattoo or piercing;
– did manicure, pedicure, any injection procedures with a non-sterile instrument;
– planning the birth of a child;
– wants to be confident in the state of his health and the health of his loved ones.

Rapid HIV tests. Can trust?

According to statistics, 30% of the total number of HIV patients in our country do not even know that they have this disease. And this means that they are very at risk of starting the disease and transferring it to AIDS. But besides this, they put the people around them at risk, which means: the disease spreads, and everyone can get sick. How can you avoid this? It’s very simple – you need to test for HIV at least once a year. To do this, you can contact any healthcare organization that has a treatment room, undergo an examination and be confident in your status.But sometimes there are situations when it is not possible to quickly undergo full medical testing. For such situations, they came up with an excellent solution – rapid HIV tests. With the development of technology, they are becoming more accurate and in many ways are not inferior to laboratory testing. Every year there are more and more of them, the choice becomes more and more diverse. In order to guide you in this variety, we will try to tell you the main points about express tests.

One should start with the fact that there is 2 of the type of express tests:

• based on saliva;
• on a blood sample.

The most popular rapid test is the saliva sample test. This is not surprising, because it is the easiest to use and does not require complex manipulations or skin damage. In addition, this test minimizes the possibility of HIV transmission. It is a device that can only be used once. To determine the presence of the human immunodeficiency virus, it is necessary to collect the pericardial fluid – saliva. The result will be ready in 20 minutes. The test determines the presence of HIV types 1 and 2 in the body.The accuracy of the test is quite high, according to some sources it is close to 99%. However, according to experts, if the test is positive, there is no need to sound the alarm and make a final diagnosis. In any case, for an accurate result, it is necessary to undergo an examination at a health care institution.

One of the most accurate rapid tests – based on a blood sample. To determine HIV in the body, it is necessary to take blood from a finger and lower it into the device. The complexity of this test, on the one hand, is that it is necessary to break the skin, on the other hand, the virus in the blood from a finger can be stored for no more than 2-3 minutes, so the material must be used immediately to determine the test results.This type of testing is carried out in health care organizations.

Rapid tests can also be performed at home if there are serious reasons for this. It must be remembered that in order to increase the accuracy of testing, you need to observe precautions and disinfection, strictly follow the instructions. Well, if you read this instruction in full, then you can see there information that in order to confirm the results of express tests, you need to be re-tested in a polyclinic. Do not forget about this in order to have a 100% result and be confident in your status.

90,000 Where, how and why Petersburgers to take an HIV test

It is not only “vulnerable” population groups that are at risk of HIV infection. Most of the cases of infection have long been detected among the “socially prosperous” Petersburgers.

Where you can get anonymous and free of charge examinations, what tests for HIV exist and how reliable they are, Dr. Peter found out.

In Russia, HIV has long gone beyond the “risk groups”, which traditionally include drug users, sex workers and men who have sex with men.“There are no“ risk groups ”- people who are more susceptible to infection than others. There are risky behaviors that anyone can practice under different circumstances, ”says the AIDS Center. In St. Petersburg, among patients with HIV who have been identified over the past five years, almost 70% are sexually infected. Most of them are those who are called socially well-off.

For many years, the virus may not manifest itself in any way, gradually destroying the immune system.Timely detection of HIV can preserve one’s own health, the health of a partner and future children. A timely detected disease makes it possible to start antiretroviral therapy earlier, which suppresses the activity of the virus. With the correct use of drugs, the viral load is reduced to undetectable (zero), which means that it is no longer possible to transmit HIV.

HIV testing can give an accurate answer – however, after risky contacts, time must pass. All modern HIV tests, which are carried out at the first stage, do not detect the virus itself in the body – they only show the presence of antibodies to the virus or antigens in it.But even with HIV infection, antibodies to it do not appear immediately. Therefore, from 2 weeks to 6 months (and in very rare cases – up to a year), the “window period” can last – when the virus has already entered the body and multiplies, but antibodies in the blood have not yet appeared, and therefore the HIV test at this time can be negative.

Rapid HIV tests are usually done in mobile laboratories. They give results very quickly (in about 20 minutes), are easy to carry out and are reliable.However, as experts note, the diagnosis is not established based on the results of express testing; to confirm the result, you need to contact a specialized institution, where an examination will be carried out by other methods. Rapid tests can be done on a saliva sample and on a blood sample. They determine the presence in the body of antibodies to HIV types 1 and 2. The accuracy is confirmed by research – it reaches about 99%. Rapid tests can also be done at home. This requires strict adherence to instructions and precautions and disinfection measures.

One of the modern HIV studies is the enzyme-linked immunosorbent assay (ELISA), which is used during the initial examination in medical institutions. If the result is positive, the patient is sent for a confirmatory blood test – immune blotting – a more sensitive and specific method. And already the polymerase chain reaction (PCR) determines not the presence of antibodies to HIV, but the virus itself in the body. PCR is prescribed after the above studies for the final confirmation of the result and in certain clinical situations: when there is a risk of vertical transmission of HIV from mother to child, or when an acute infection is suspected in a patient.

For an HIV test, you can contact your physician at the local polyclinic with a request for a referral for an HIV blood test. In all city polyclinics there is an opportunity to make a free blood test by the enzyme immunoassay. It is possible to get tested for HIV anonymously, and it is also free of charge. In St. Petersburg, this can be done at the City Center for the Prevention and Control of AIDS or at mobile centers.

Center for the Prevention and Control of AIDS and Infectious Diseases

You can read the text in the Center in Anonymous office (office 109), which is located on the 1st floor of the AIDS Center polyclinic, at the address: nab.Obvodny Canal, 179. It works from 9.00 to 19.00, on Fridays – from 9.00 to 13.00. Consultations are held free of charge and anonymously, without an appointment, without providing documents and regardless of whether the applicant has a registration in St. Petersburg or not. Before the examination, the specialist asks to fill out a questionnaire, without specifying personal data, after which the applicant receives advice on HIV / AIDS issues, and then donates blood for research in the treatment room No. 107.

Treatment room No. 107 is open from Monday to Thursday from 9:00 to 19:00 and on Friday from 9:00 to 13:00.For an anonymous HIV test, you need to come to the appointment in advance (30 minutes before the end of the procedure room). This is due to the fact that filling out the questionnaire and consultation take time, and the reception is carried out on a first-come, first-served basis.

The time when you can take the test result will be indicated on the coupon that the patient receives after taking blood. The test results are given to the person being examined personally, they are not reported by phone.

Also Monday to Friday from 12.00 to 18.00 at the Center works HIV prevention point : nab. Obvodny Canal, 179 (in the courtyard, entrance under the arch and to the right).

AIDS Center hotline +7 (812) 955-27-00 (Monday to Thursday from 9.30 to 17.00)

Clinical Infectious Diseases Hospital named. S.P. Botkin

HIV prevention point : Mirgorodskaya st., 3, (entrance from Kremenchugskaya street, to the reception area).Monday-Friday from 9.00 to 16.00. Phone +7 (812) 717-89-77

You can also take the test anonymously and free of charge at the hospital itself. The test result is announced only orally.

Mirgorodskaya st., 3 (polyclinic building). Open from Monday to Friday 8.30-15.00. Reception phone +7 (812) 325-98-54

Piskarevsky prospect, 49. From Monday to Thursday 8.00-16.00, Friday – until 15.00. Reception phone +7 (812) 777-80-11.

City Narcological Hospital, Petrograd Branch

HIV prevention point : Bolshaya Pushkarskaya st., 13. Blood sampling for HIV (as well as hepatitis B and C, syphilis) is done by specialists on Mondays from 9.30 to 18.00 (only from October 15). The result is in 10 working days. From Monday to Friday, from 9.30 am to 7 pm, you can seek counseling and other HIV prevention help. Phone +7 (812) 232-86-03

Center for the Prevention and Control of AIDS and Infectious Diseases of the Leningrad Region

Petersburg, st.Mira, 16, 2nd floor, rooms 13, 14 (express testing and anonymous office). Monday to Friday from 9:00 am to 4:00 pm. The HIV hotline for residents of the Leningrad Region operates during the same working hours +7 (911) 927-65-68

Mobile units of a public organization “ Humanitarian action ”

In several districts of St. Petersburg, near metro stations, there are mobile laboratories , where you can make an express HIV test free of charge and anonymously and get specialist advice.To find out where they are on duty, you need to call the “hot lines” of the projects:

“Prevention of HIV infection among the general population” – from Monday to Friday from 13:00 to 18:00, and on Wednesdays – from 14:00 to 19:00 by phone +7 (952) 362-90-68

“Prevention of HIV- infection among drug users ”- from Monday to Friday from 10.00 to 22.00 by phone +7 (952) 362-87-85

“ Prevention of HIV infection among sex workers ”- from Monday to Friday from 10.00 to 22.00 by phone +7 (931) 210-30-07

Mobile office of the fund “ Diaconia ”

Rapid HIV testing can be done at at the mobile prevention center “Bus of Mercy”.

HIV testing hotline +7 (812) 642-62-68

Bus phone +7 (964) 342-62-68

Low threshold point “ Vereiskaya 23 ”

HIV testing is carried out from 12:00 to 15:00 at Vereiskaya st., 23.

Phones: +7 911 928 85 31 (10.00-22.00), +7 (812) 907-23-69 (15.00-6.00)

The point works for “vulnerable” groups of the population.

Initiative Support and Mutual Help Group “ No HIV OK ”

A support group is donating HIV self-test kits to men who have sex with men and transgender people.Tests are handed out in the office of the AIDS Center, as well as in nightlife venues in St. Petersburg. For information, please contact the project curator Pavel by phone +7 (906) 279-29-33.

Based on materials from the portal Doctor Peter

90,000 Saliva sensitivity of HIV diagnostics increased a thousand times

HIV-1 (colored green).

C. Goldsmith / Centers for Disease Control and Prevention

The new saliva test for HIV allows you to diagnose the disease with one hundred percent accuracy and high sensitivity, even in the early stages.The test uses immuno-PCR techniques that increase small concentrations of antibodies, making it 1,000 to 10,000 times more sensitive than the clinical tests still in use, according to American scientists in the journal Proceedings of the National Academy of Sciences .

HIV has long been able to diagnose with high accuracy, but a blood sample is best for this, and because of which there is a problem of insufficient coverage: people do not like to donate blood and are not tested as often as doctors recommend, even if they are in a group risk.They are trying to solve the problem of coverage by the introduction of self-diagnosis kits, rapid tests, and diagnostics using a saliva sample, but in the latter case, another problem arises: it is difficult to detect low levels of antibodies in a saliva sample, which means that those people who have recently become infected can get a false negative result. For example, the OraQuick rapid test is able to detect HIV no earlier than 40 days after infection, and for tests on a blood sample, the delay is 14 to 24 days.The lower the antibody concentration at which the diagnosis becomes effective, the shorter this window, but increasing the sensitivity of the test is a challenging research task, which scientists led by Cheng-ting Tsai from Stanford University have tackled.

Researchers have created a test based on the immuno-PCR (ADAP) methods that have been tested in the past. PCR methods can increase small concentrations of certain DNA fragments and are used, in particular, for the diagnosis of infectious diseases.Immuno-PCR amplifies the desired antibodies to detectable levels. They are also convenient because different antibodies against HIV can be detected in one sample.

To test the sensitivity of the test, the scientists developed antibodies against the capsid protein p24 and the glycoproteins gp41 and gp160, diluted them, and compared the antibody concentrations that were shown by a conventional clinical test ( Avioq microelisa ) and a new one. Scientists have found that the success of detecting antibodies depends on both the type of antibody and the concentration.The test they developed made it possible to detect these antibodies within 110, 880 and 550 zeptomoles for antibodies to p24, gp41 and gp160, and for the clinical enzyme immunoassay the limits were 8.5, 9.2, and 11 femtomoles (moles at minus 15 degrees), respectively. In sum, this means that the sensitivity of the new test turned out to be 1000-10000 times higher.

Sensitivity of the new test (ADAP) versus the commonly used one (EIA).The x-axis indicates the amount of antibodies (in moles), the y-axis on the left indicates the results of a new test, and the y-axis on the right indicates the results of a conventional test.

Cheng-ting Tsai et al., Proceedings of the National Academy of Sciences, 2018

The test was then tested on saliva samples that had previously been diagnosed by enzyme-linked immunosorbent assay (EIA). 22 samples were HIV positive, another 22 samples were HIV negative, and eight samples were classified as “doubtful”.The test was able to detect antibodies to p24, gp41, gp120 and gp160, the difference between HIV-positive and HIV-negative samples was significant (p

Despite successful results, the test has yet to be confirmed on other subtypes of HIV-1, more tests to be performed, and the window during which the test is useless However, this is an important area of ​​work, because in addition to convenience and coverage, saliva smear diagnostics is also safer, since the collection of saliva for analysis does not carry the risk of infection.The weak point, however, remains the human factor, because self-diagnosis requires very careful observance of the instructions, and violation of any of them threatens to obtain an incorrect result.

If you do not take medication, HIV infection develops into AIDS. Answers to frequently asked questions about HIV and AIDS are published on the WHO website.