Frequently Asked Questions about the PSA Blood Test | Roswell Park Comprehensive Cancer Center

As we grow older, our risk of developing serious health issues, including cancer, also grows. For men, the risk of getting prostate cancer increases with age. Prostate cancer is rare in men under 40, and about 60% of cases are diagnosed in men aged 65 or older. But in the United States, nearly one of every nine men will be diagnosed with the disease. That’s why doctors recommend screening for prostate cancer beginning at age 45, with a yearly digital rectal exam and PSA blood test.

But what is exactly is a PSA test and what does it measure? When should you consider starting your screening for prostate cancer? We’ve compiled answers to these and other frequently asked questions about PSA tests here.

What is a PSA test?

Prostate-specific antigen (PSA) is a protein produced by the prostate gland that is present in small quantities in all men’s blood. It often is elevated in the presence of prostate cancer, making a man’s PSA levels a useful tool for early prostate cancer detection.

The PSA blood test was developed at Roswell Park Comprehensive Cancer Center in the 1970s and is now in use worldwide. Since the test was first introduced, the cure rate for prostate cancer has increased from about 4% to 80%. Here are some answers to the frequently asked questions we receive from men preparing for their first PSA exam.

How is the PSA test done?

A PSA test is performed the same way as other routine blood tests. A small vial of blood is drawn from the arm and brought to a laboratory where PSA levels are measured as the number of nanograms (ng) in each milliliter (mL) of blood tested.

What is a normal PSA value?

A PSA level between 2.5 and 4 ng/mL is considered a normal PSA level for most men, but this depends on many factors, such as the patient’s age, prostate size and a variety of patient activities (for example, bike riding).  A PSA level greater than 4 ng/mL may be normal for some men.  A physician must interpret whether the PSA level is normal for each individual.

What does a PSA test do?

As mentioned above, a PSA test measures the amount of prostate-specific antigen (PSA) found in a man’s blood. Many factors including prostate cancer can cause someone’s PSA levels to rise. A PSA test is designed as an early detection and monitoring screening tool for prostate cancer.

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Do you have to fast for a PSA test?

No, fasting is not required before a PSA test.

When should a man start PSA testing?

Roswell Park follows PSA screening guidelines established by the National Comprehensive Cancer Network (NCCN), which brings together world-renowned experts from 30 of the nation’s top cancer centers to write guidelines that specify the best ways to prevent, detect and treat cancer.

Current guidelines include recommendations to start PSA screening at age 40 if you are African-American, or if you have a father or brother who had prostate cancer — especially if they were younger than 60 at the time of diagnosis — or if you have undergone genetic screening that showed you have a genetic mutation (such as BRCA1, BRCA2, ATM, HOXB13, MLh2, MSh3 or MSH6).

If you do not fall into any of the groups above, you may consider beginning early detection with a baseline PSA test and digital rectal exam at age 45. The results of these tests will be used to compare with future tests. If your first PSA test shows a level of 1.0 ng/mL or higher, you should undergo follow-up testing every one to two years. If your first PSA test shows a level less than 1.0 ng/mL, you should have follow-up testing every two to four years.

A PSA test is generally not recommended for men over the age of 75 unless they are very healthy and have a life expectancy of 10 years or more.

You should discuss the pros and cons of having a PSA test with your doctor. If you do receive a PSA test, your doctor will need to put the results in perspective with your age, how long you can be expected to live, your family medical history, your race and the results of any previous PSA tests.

A population study of fasting time and serum prostate-specific antigen (PSA) level

Asian J Androl. 2014 Sep-Oct; 16(5): 740–744.

Published online 2014 Jun 24. doi: 10.4103/1008-682X.125912

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Author information Article notes Copyright and License information Disclaimer

Prostate cancer is one of the most common cancers in men. Traditional screening and diagnostic methods include digital rectal examinations (DREs), biopsies and serum prostate-specific antigen (PSA) tests, with the latter being the more popular. PSA is a biomarker for prostate cancer; however, it is highly sensitive to external factors as well as other prostate diseases. As such, the reliability of of the serum PSA level as a sole screening and diagnostic tool for prostate cancer is controversial. Recently, it has been shown that fasting extremes can affect concentrations of serum chemistry analytes, thus raising the question of whether or not fasting has an effect on the highly sensitive PSA biomarker. Patients testing for serum PSA levels are often concomitantly submitting to other tests that require fasting, subjecting certain patients to a fasting PSA level while others not. The objective of this study was to investigate whether this discrepancy in fasting state translates into an effect on serum PSA levels. Serum PSA levels and fasting time records for 157 276 men who underwent testing at Calgary Laboratory Services (CLS; Calgary, Alberta, Canada) between 01 January 2010 and 31 March 2013 were accessed. Linear regression models of mean PSA levels and fasting times revealed a statistically important relationship at certain fasting times. Applying a dynamic mathematical model to explore the clinical effect of fasting suggests minimal impact on serum PSA result interpretation. Thus, patients can be tested for serum PSA levels regardless of their fasting state.

Keywords: diagnostic test, fasting, prostate-specific antigen (PSA)

Prostate cancer is the most common form of cancer diagnosed in Canadian men.1 The Canadian Cancer Society estimates that in the year 2013, there will be 23 569 new cases of prostate cancer.2 As such, discovering and developing novel biomarkers for prostate cancer screening are of utmost importance.3,4,5 Traditionally, digital rectal examination (DRE) has been the preferred assessment method for prostate cancer.6 In the 1980s, the serum prostate-specific antigen (PSA) test was introduced as an additional method for screening, diagnosing and monitoring treatment of patients with prostate cancer.7 PSA testing was not highly utilized in Canada until 1990.8 As a result of its increased utilization, the incidence rate of prostate cancer detection increased rapidly and peaked in 1993.9 Serum PSA testing is currently one of three common procedures: DRE, serum PSA test and transrectal ultrasound-guided biopsy, used to screen and diagnose prostate cancer. 10

Serum PSA testing has, however, courted controversy because of its low specificity. Despite its shortcomings, PSA is still the most common and preferred screening method within the male population due to its convenience and accessibility. North American prostate cancer screening guidelines recommend that men with a family history of prostate cancer or of African descent should begin screening at 40 years of age.7,11 For the rest of the male population, screening should commence at the age of 50 years.7,11 Currently, physicians are responsible for informing patients of the availability of the different prostate cancer screening options and their associated risks to assist the patient in making informed screening decisions.12 For prostate cancer screening, it is advocated that a DRE is performed in conjunction with serum PSA testing. Serum PSA levels, however, are highly sensitive and can be easily altered by prostate stimuli. PSA is a glycoprotein produced by prostate epithelial cells that line the ducts and acini of the prostate. 13 Any type of stimuli that causes a disruption of the innate glandular architecture of the prostate can facilitate PSA to enter systemic circulation, which leads to increased levels.13 Apart from physical stimulation of the prostate, other conditions that elevate serum PSA concentrations from baseline include: benign prostatic hyperplasia (BPH), prostatitis, urethral instrumentation, prostate biopsy and prostate cancer.13,14 Other causes of PSA elevation are vigorous DRE and recent ejaculation.13,15

Since the levels of serum PSA are highly responsive to its environment, we would like to investigate if diagnostic testing conditions, specifically fasting, can affect PSA results. Fasting is not required for serum PSA testing; however, serum PSA tests are often performed in combination with other diagnostic tests that do require fasting. Other common laboratory tests that have been examined for the relevance of fasting time have shown that at fasting extremes (such as less than 1 h or over 12 h) the effects of hemodilution/hemoconcentration are observed. 16,17 A previous limited study by Tuncel et al.18 examined fasting time and serum PSA levels. In their study, 80 patients were asked to fast between 12 am and 8 am, after which they were provided breakfast and lunch. Serum samples were obtained periodically pre- and post-meals to monitor its effect on serum PSA levels.18 They reported that there was no difference between pre- and post-prandial serum PSA levels.18 Their findings however, are limited by a small sample size and limited fasting times examined.18 Thus, the objective of our study is to revisit this topic by examining a wider range of fasting times and a larger data set: the community population of Calgary, Alberta. We hypothesize that fasting should not affect serum PSA levels except at fasting extremes where the effects of hemodilution/hemoconcentration may play a role.

Ethics statement

This study was approved by the University of Calgary Conjoint Health Review Ethics Board (ID: E-25060).

Study population and data sources

This study was conducted using secondary data from the Laboratory Information System of Calgary Laboratory Services (CLS). CLS is the sole provider of laboratory services for Calgary, Alberta and its surrounding areas (approximately 1.4 × 106 people). The study population consisted of all men who underwent PSA testing at CLS between 01 January 2010 and 31 March 2013. All PSA tests were performed as part of routine patient care and were analyzed at CLS using a Roche Modular analyzer. Fasting time (hours) was obtained through patient self-reporting at the time of testing. In our analysis, fasting time was categorized into hourly intervals from 1 to 16. All reported fasting hours were rounded up to the next integral value. All individuals with a fasting time beyond 16 h were grouped into the 16 h category. PSA records were excluded for female patients, probable cancer patients (serum PSA level >20 μg l^–1) and if a fasting time was not recorded. As age-specific reference ranges are only commonly reported for men between the ages of 40 and 79 years, any records outside of this range were also removed. Finally, to avoid pseudoreplication we considered only the first PSA result from each patient. This resulted in a total of 157 276 PSA records and paired fasting times.

Statistical analysis

Fasting time for laboratory tests has been shown to vary as a function of age and sex.19 As our study only consists of males, the effects of sex on fasting time are negated. The data were fitted to a linear regression model with serum PSA measurement as the dependent variable and fasting time (in hours) and age (10-year cohorts) as independent variables. Estimated marginal means were calculated based on 95% confidence intervals at each fasting time period, with age held constant at the group mean. Statistical significance was assessed through pairwise comparison of fasting hours and its corresponding serum PSA levels using the Tukey post hoc test. All statistical analyses were performed using the Statistical Package for Social Sciences (SPSS) software (Version 20 for Windows, SPSS Inc. , Chicago, IL, USA).

Dynamic mathematical model

To explore the impact of fasting time on serum PSA levels through a clinical perspective, a dynamic mathematical model was developed to calculate the percentage of individuals expected to experience a change in PSA diagnostic interpretation (e.g. normal vs abnormal result) based on variations in fasting time. In this model, data were first parsed into age cohorts: 40–49, 50–59, 60–69 and 70 to 79-years-old, and the number of PSA values above of the normal range (2.5, 3.5, 4.5 and 6.5 μg l^–1 respectively, based on age-dependent cutoffs) were calculated. In order to preclude ethnicity-related serum PSA effects, and since ethnicity data are not collected during PSA testing, only age-specific reference ranges for Caucasian males were used. PSA cutoff levels for an abnormal test were based on the Alberta Toward Optimized Practice 2010 guidelines.11 We included only paired fasting time intervals that showed a statistically significant (P < 0. 05) difference in mean PSA value (see Results section). For each of these paired fasting times, we calculated the expected difference in serum PSA value if the patient had fasted for the other period of time. These calculations were performed by adding (or subtracting) the differences in estimated marginal means to each individual result. For example, results for patients with a 4 h fasting interval were modified to simulate a 9 h fasting interval by subtracting 0.367 from every value (the mean difference attributable to fasting time; ). Following this operation, we recalculated the number of abnormal PSA results for each simulated change in fasting time. These are presented as a projected percent change in abnormal results due to a change in fasting time and allow us to comment on the anticipated clinical significance of variations in fasting time.

Table 1

Dynamic mathematical model results showing modeled effects of changes in fasting time on abnormal PSA (>upper limit of normal) classification rates

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A total of 157 276 PSA records were accessed from our Laboratory Information System. The mean PSA level for all records was 1.35 μg l^–1. The average age of patients tested was 57.0 years of age. The average fasting time of all records was 12.7 h with a minimum and maximum fasting time of 1 and 16 h, respectively. Mean PSA levels at different fasting times are shown in . illustrates the dependence of each independent variable (fasting time and age) on the dependent variable (serum PSA levels). These results indicate that fasting time and age have a statistical effect on serum PSA levels. shows the specific fasting hours that have an effect on serum PSA levels. At fasting times (>8 h), serum PSA levels are generally distinct from non-fasting times (1–8 h).

Table 2

Serum PSA levels by fasting time after adjustment for the effect of age

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Table 3

Univariate analysis of variance showing the effect of fasting time on serum PSA value

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Table 4

Multiple mean comparison between fasting hours and serum PSA values adjusting for age effects

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Although a number of variations in fasting time yielded statistically important results, we were also interested in assessing the potential clinical significance of these changes. A Dynamic Mathematical Model as described earlier showed that an increased fasting time would generally result in a modest increase in the number of patients with abnormal PSA values ( and ). The overall changes in classification (normal to abnormal or vice versa) ranges from −1.07% to 1.63% (mean = 0.19%; ).

Previous studies have shown that different fasting states can affect chemical analytes.16,20 Specifically, it has been suggested that the ingestion of food can trigger different physiological responses that affect blood biochemical markers commonly used in laboratory tests.20 For example, the serum concentration of liver biomarkers aspartate aminotransferase and alanine aminotransferase has been shown to notably increase 4 h after meal ingestion.20 Apart from changes in the levels of liver biomarker enzymes, variations in red blood cell count, hematocrit and hemoglobin concentrations have also been noted.16 These changes are attributed to hemodilution of the blood where an increase in blood volume alters the constituent. 16 Another analyte that has been examined for the effects of fasting is cholesterol.17 Traditionally, testing of total lipids and lipid subclass levels were performed in a postprandial state of 8 or more hours.21,22 However, recent work has suggested that fasting is largely unnecessary for routine lipid level.17 However, at fasting extremes (14–16 h), statistically important differences exist.17 In this study, we wanted to examine whether such fasting extremes have an effect on serum PSA levels, a prostate biomarker that is highly sensitive to environmental conditions. In particular, as serum PSA tests are often performed in conjunction with other fasting laboratory blood tests, the effects of fasting could potentially alter patient treatment depending on the variation in serum PSA concentrations. A previous study performed by Tuncel et al.18 on a group of 80 individuals showed that fasting up to and including 8 h did not have an effect on serum PSA levels. To our knowledge, our study is the first to examine the effect of fasting time on serum PSA levels within a community-based population.

shows two regions of interest: 1–9 and 10–16 h. Between fasting times of 1–9 h, fluctuations exist; while at 10 h and beyond, there is a general increasing trend. A notable feature is the peak in serum PSA level observed at 4 h of fasting (). We considered collection time (as opposed to fasting interval) as a possible confounding factor which could have biased the observed increase in PSA levels at 4 h of fasting. To remove this possible bias we reperformed the analysis with collection time as an additional variable. The overall trend, however was unchanged (data not shown). A potential reason for this increase may instead be related to diurnal variation in serum PSA levels. It has been suggested that PSA expression is controlled by hormones23 and in particular, in cases of patients with BPH, testosterone has been shown to directly influence serum PSA levels24 and exhibits a well-established circadian rhythm.25 Thus, it is of interest to examine if serum PSA follows the same diurnal variation as testosterone. Diurnal variation of serum PSA has been previously examined and is controversial as some studies suggest its existence, while others disagree.26,27,28,29,30 A major potential shortcoming of these studies is their small sample size; the study with the largest sample contained 44 men.30

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Mean serum PSA levels at different fasting time not accounting for age-variance; prepared by SPSS.

The second region encompassing fasting hours of 10–16 shows a gradual increase in mean PSA values (). Analyzing the mean differences in PSA values between the different fasting times shows that at fasting extremes (1 h or less or 9 or more hours), PSA values are significantly different (). This is similar to observations for other chemistry analytes.16,17 Since the trend past 9 h is an increasing one (), it should be noted that the longer the fasting time the greater the deviation in detected PSA values. Our statistical analysis suggests that the optimal time to obtain an accurate PSA level is fasting for 7–9 h, which avoids the increased PSA levels observed with fasting extremes as well as possible diurnal rhythm variations that may exist in shorter fasting times. It should be noted that the larger standard deviations observed in serum PSA levels for 1–9 h of fasting compared to 10 or more hours () are likely the result of smaller sample sizes for these time periods (160–800 men).

To explore the clinical effect of fasting time on serum PSA levels, a dynamic mathematical model was developed. Simulating the changes that would occur in PSA values if fasting times were altered revealed that the percentage change in the number of abnormal PSA values can range from −1.07% to 1.63% (). Therefore, despite the statistical significance of PSA variations with fasting time, our model predicts that this would translate into minimal clinical effect.

There were several limitations in this study that were unaccounted for in our analysis. The first is the possibility of patient recall error regarding fasting time. Another limitation that should be noted is our use of secondary data on individuals and not a random sample of individuals taken from the general population. As such, these findings can only be interpreted as representative of individuals presenting for testing and may be a biased representation of the overall population.

In conclusion, certain fasting states (1 or less hours or 4 h or 9 or more hours) have a statistically significant effect on serum PSA levels which substantiates both our hypothesis and other previous studies that have observed deviations in concentrations of serum analytes at fasting extremes.16,17 However, when translating this to an anticipated clinical effect, we suggest this would have a minimal impact on overall classification rate of normal versus abnormal results. It appears that patients can be tested for serum PSA levels regardless of their fasting state. Future research should focus on identifying additional biomarkers and/or chemical analytes for prostate cancer that are robust and less sensitive to external stimuli. This will help reduce the ambiguity and increase the reliability associated with prostate cancer testing.

CKL, MG, JAZ and CTN participated in the conception and design of the study. JAZ acquired all relevant data. CKL, MG and CTN critically interpreted and analyzed the data. MG performed all statistical analyses. CKL and CTN drafted the manuscript. CKL, MG, JAZ and CTN all participated in the critical revision of the manuscript for intellectual content. CTN supervised the study. All authors read and approved the manuscript.

All authors declare no competing interests.

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How to properly prepare for a laboratory test

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Laboratory diagnostics

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See also other conditions for preparing for analysis.

Dear patients! Please note that it is recommended to donate blood for laboratory tests in the morning on an empty stomach, after an 8-12 hour overnight fasting period. If the patient does not have the opportunity to come to the laboratory in the morning, blood should be donated after 6 hours of fasting, excluding fats in the morning meal.

Timely and accurate diagnosis of various diseases is impossible without laboratory tests. There are no manifestations of the disease yet, and the blood counts are already “signaling”: “Attention! Anxiety!”.

According to the World Health Organization (WHO), laboratory tests provide 60 – 80% of diagnostic information about the patient. Of course, only one laboratory analysis does not make a diagnosis, it is compared with the clinical picture, with the data of other studies and observations. Laboratory analysis suggests the direction for further search. Therefore, regular preventive examinations are the key to the timely start of treatment, and proper preparation for testing in a modern laboratory is an accurate diagnosis.

The laboratory doctors of the Independent Laboratory INVITRO have prepared a number of recommendations, the observance of which will allow you to get the most accurate results.

• How to prepare for a blood test
• How to prepare for a urine test
• Rules for the collection of feces for dysbacteriosis

Preparing the patient for blood donation

1. A number of tests are done on an empty stomach. For example, biochemical (glucose, cholesterol, bilirubin, etc.) and serological tests (syphilis, hepatitis B), hormones (TSH, parathyroid hormone), etc. “Fasting” is when at least 8 hours pass between the last meal and blood sampling (preferably at least 12 hours). Juice, tea, coffee, especially with sugar, are also food, so you have to be patient. You can drink water.
2. Strictly on an empty stomach (after a 12-hour fast), you should donate blood to determine the parameters of the lipid profile: cholesterol, HDL, LDL, triglycerides.
3. If you have to take a complete blood count, the last meal should be no later than 1 hour before blood donation. Breakfast may consist of unsweetened tea, unsweetened porridge without butter and milk, an apple.
4. It is advisable to exclude fat, fried foods and alcohol from the diet 1-2 days before the examination. If there was a feast the day before, postpone the laboratory test for 1-2 days. Refrain from smoking one hour before blood sampling.
5. The content of many blood tests is subject to diurnal fluctuations, therefore, for some studies, blood should be donated strictly at certain times of the day. So, blood for some hormones (TSH and parathyroid hormone), as well as for iron, is taken only until 10 am.
6. When donating venous blood, it is necessary to exclude factors that affect the results of the research: physical stress (running, climbing stairs), emotional arousal. Therefore, before the procedure, you should rest for 10-15 minutes in the waiting room, calm down.
7. It happens that the doctor ordered an examination, but for various reasons it is difficult for the patient to come to the medical office (illness, pregnancy, lack of time, etc.). In this case, it is enough to call the INVITRO Laboratory Emergency Service by calling tel. +7(495)363-03-63, and our procedural team will arrive at a convenient place and time for you.
8. Blood for analysis is taken before the start of taking medications (for example, antibacterial and chemotherapeutic drugs) or not earlier than 10-14 days after their cancellation. The exception is when they want to study the concentration of drugs in the blood (for example, valproic acid, anticonvulsants). If you are taking medication, be sure to tell your doctor about it.
9. Blood should not be donated after x-rays, rectal examinations, or physiotherapy procedures.
10. In hormonal studies in women of reproductive age (from about 12 to 13 years of age until the onset of menopause), the results are influenced by physiological factors associated with the stage of the menstrual cycle. Therefore, when preparing for an examination for the hormones FSH, LH, prolactin, estriol, estradiol, progesterone, the phase of the cycle should be indicated. When conducting a study on sex hormones, strictly adhere to the recommendations of your doctor about the day of the menstrual cycle on which you need to donate blood.
11. When performing tests for infections, be aware that depending on the period of infection and the state of the immune system, any patient may have a negative result. But, nevertheless, a negative result does not completely exclude infection. In doubtful cases, it is recommended to re-analyze.
12. Different laboratories may use different test methods and units of measurement. In order for your results to be assessed correctly and the results to be acceptable, do research in the same laboratory, at the same time. Comparison of such studies will be more correct.

Preparing the patient for urination

Collecting urine for general analysis in a container with preservative

1. At the medical laboratory office, obtain a container with a white cap and a test tube with an adapter.

2. On the eve of the test, it is recommended not to eat vegetables and fruits that can change the color of urine (beets, carrots, etc.), not to take diuretics. Before collecting urine, it is necessary to make a thorough hygienic toilet of the genital organs. Women are not recommended to take a urine test during menstruation.

3. Collect approximately 50 ml of morning urine in a container (with a white lid). For the correct examination during the first morning urination, a small amount of urine (the first 1 – 2 seconds) should be released into the toilet, and then, without interrupting urination, substitute a container for collecting urine, in which to collect approximately 50 ml of urine.

4. Close the container tightly with the screw cap immediately after collecting the urine.

5. Insert the adapter into the container, pressing its sharp end into the recess on the container (Fig. No. 1).

6. Push the tube down with the rubber stopper into the recess on the wide part of the adapter, and the tube will begin to fill with urine. After the urine stops flowing into the tube, remove the tube from the adapter (Fig. No. 2, No. 3).

7. Invert the tube several times for better mixing of urine with preservative (Fig. No. 4).

8. Deliver the tube with urine to the laboratory during the day (according to the blood test schedule). If it is not possible to immediately deliver urine to the medical office of the laboratory, then the tube with urine should be stored at a temperature of +2…+8°C.

Daily urine collection for biochemical analysis

Daily urine collection. The first morning portion of urine is removed. All subsequent portions of urine allocated during the day, night and the morning portion of the next day are collected in one container, which is stored in the refrigerator (+4 … + 8 ° C) during the entire collection time (this is a necessary condition, since at room temperature significantly reduces the glucose content). After completing the collection of urine, accurately measure the contents of the container, be sure to mix and immediately pour into a small jar (no more than 5 ml). Bring this jar to the laboratory for analysis. You don’t have to bring all the urine. On the referral form, you need to indicate the daily volume of urine (diuresis) in milliliters, for example: “Diuresis 1250 ml”, write also the height and weight of the patient.

Before 10 am (1st or 2nd morning urine), a urine sample is taken to determine DPID.

Urine collection for analysis “Catecholamines in urine”

To conduct the study, it is necessary to obtain a preservative powder and a container for urine at any INVITRO medical office. Before a planned urine collection for the determination of catecholamines, preparations containing rauwolfia, theophylline, nitroglycerin, caffeine, ethanol should not be used for 3 days, if possible, do not take other drugs, as well as food products, serotonin content (chocolate, cheeses and other dairy products , bananas), do not drink alcohol. Avoid physical activity, stress, smoking, pain effects that cause a physiological rise in catecholamines.

Previously, a preservative powder from a test tube obtained in the laboratory is poured onto the bottom of a clean container into which urine will be collected. The bladder is emptied (this portion is poured out), the time is recorded and urine is collected in a container with a preservative exactly during the day, the last urination into the vessel should be 24 hours from the recorded time (for example, from 8.00 am to 8.00 am the next day). It is possible to collect urine for 12, 6, 3 hours or a single portion, preferably in the daytime.

At the end of the collection period, measure the total volume of urine excreted per day, mix it, pour a part into a specially issued container and immediately bring it to the study. When submitting the material, be sure to note the time of collection and the total volume of urine.

Remember that only the attending physician, who has the opportunity to observe the patient’s condition and explain the need for prescribing certain tests, can draw up an optimal laboratory examination program and evaluate the test results.

IMPORTANT!

The information in this section should not be used for self-diagnosis or self-treatment. In case of pain or other exacerbation of the disease, only the attending physician should prescribe diagnostic tests. For diagnosis and proper treatment, you should contact your doctor.
For a correct assessment of the results of your analyzes over time, it is preferable to do studies in the same laboratory, since different laboratories may use different research methods and units of measurement to perform the same analyzes.

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Rules for preparing for testing

Are you going to get tested? We have prepared for you a memo with recommendations and rules for passing various types of tests to obtain the most accurate results.

General rules:

1. For most tests, it is recommended to donate blood in the morning, between 8 and 11 am, on an empty stomach (at least 8 hours must elapse between the last meal and blood sampling, water can be drunk as usual), On the eve of the study, a light dinner with restriction of fatty foods. For infection tests and emergency investigations, it is acceptable to donate blood 4-6 hours after the last meal.
2. ATTENTION! Special preparation rules for a number of tests: strictly on an empty stomach, after 12-14 hours of fasting, you should donate blood for gastrin-17, lipid profile (total cholesterol, HDL cholesterol, LDL cholesterol, VLDL cholesterol, triglycerides, lipoprotein (a), apolipo -proten A1, apolipoprotein B), glucose tolerance test.
3. On the eve of the study (within 24 hours), exclude alcohol, intense physical activity, taking medications (as agreed with the doctor).
4. 1-2 hours before donating blood, refrain from smoking, do not drink juice, tea, coffee, you can drink non-carbonated water. Eliminate physical stress (running, fast climbing stairs), emotional arousal. It is recommended to rest and calm down 15 minutes before donating blood.
5. Do not donate blood for laboratory testing immediately after physiotherapy, instrumental examination, X-ray and ultrasound examinations, massage and other medical procedures.
6. When monitoring laboratory parameters in dynamics, it is recommended to conduct repeated studies in the same conditions – in the same laboratory, donate blood at the same time of day, etc.
7. Blood for research should be taken before starting medications or no earlier than 10-14 days after stopping them. To evaluate the control of the effectiveness of treatment with any drugs, it is necessary to conduct a study 7-14 days after the last dose of the drug.

If you are taking medication, be sure to tell your doctor.

The general rules apply to all assays, but some assays require special preparation and additional restrictions. It is very important to strictly follow the recommendations below, since only in this case reliable research results will be obtained.

Complete blood count

Blood is given in the morning on an empty stomach (or in the afternoon/evening, 4-5 hours after the last meal). 1-2 days before the study, exclude foods high in fat from the diet.

Urinalysis

On the eve of passing urine for analysis, it is not recommended to eat fruits and vegetables that can change the color of urine (beets, carrots, etc.), not to take diuretics, to avoid significant physical exertion.

Before collecting urine, it is necessary to carry out a thorough hygienic toilet of the genitals. Women are not recommended to take tests during menstruation.

For proper collection of material, a small amount of urine (the first 1-2 seconds) should be released into the toilet, and then, without interrupting urination, substitute a container for collecting urine. For donation, you need to collect approximately 50 ml.

The material must be delivered to the laboratory in the morning of the same day. You should not store urine for a long time, because. this leads to a change in its physical properties, the multiplication of bacteria and the destruction of sediment elements.

Biochemistry

Urea

1-2 days before the study, you must follow a diet: refuse to eat food rich in purines – liver, kidneys, and also limit meat, fish, coffee, tea in the diet as much as possible. Intense physical activity is contraindicated.

Cholesterol, lipoproteins

Lipid-lowering drugs should be discontinued two weeks prior to the study, unless the goal is to determine the lipid-lowering effect of therapy with these drugs.

Glucose

When donating blood for glucose (in addition to the basic requirements for preparing for tests), do not brush your teeth and chew gum, drink tea / coffee (even unsweetened). A morning cup of coffee will drastically change your glucose levels. Contraceptives, diuretics and other medications also have an effect.

Glucose tolerance test

Performed only if preliminary fasting glucose results are available, without exercise. The content of glucose in the blood plasma is determined on an empty stomach and 2 hours after a glucose load.

It is necessary to follow a normal diet (with a carbohydrate content of more than 125-150 g per day) and adhere to the usual physical activity for three days before the study. The study is carried out in the morning on an empty stomach after an overnight fast for 12-16 hours (at this time you can not smoke or drink alcohol).

During the examination, the patient should lie or sit quietly, do not smoke, do not get cold and do not engage in physical work.

It is not recommended to conduct a study after and during stressful effects, after operations and childbirth, with inflammatory processes, alcoholic cirrhosis of the liver, hepatitis, during menstruation, with gastrointestinal diseases with impaired glucose absorption.

Medical procedures and medications (epinephrine, glucocorticoids, contraceptives, caffeine, thiazide diuretics, psychotropic drugs and antidepressants) must be excluded before the test.

Cancellation of drugs is made only after prior consultation of the patient with the doctor.

CHILD UNDER 14 glucose tolerance test not performed.

PREGNANT Glucose tolerance test is recommended at 24-28 weeks of gestation, it allows to identify up to 98% of women with gestational diabetes.

Haptoglobin

Before the study, it is necessary to exclude the use of drugs: dapsone, methyldopa, sulfasalazine, estrogens, oral contraceptives, tamoxifen, androgens.

Alpha-2-macroglobulin

Refrain from eating meat for three days before the test.

FibroTest, FibroMax, SteatoScreen

Blood sampling is carried out strictly on an empty stomach in the morning. 1-2 days before the study, it is not recommended to take ascorbic acid, it is also necessary to exclude drugs and products that cause artificial coloring of the serum (carrot, orange).

For the FibroMax study, you must specify your exact weight and height.

Hormones

Blood for hormonal tests should be taken on an empty stomach in the morning. In the absence of such an opportunity, blood can be donated for some hormones 4-5 hours after the last meal in the daytime / evening hours (except for those studies for which blood must be donated strictly in the morning).
1-2 days before the test, exclude high-fat foods from the diet, the last meal should not be plentiful. Psycho-emotional and physical comfort (a calm state without overheating and hypothermia) is necessary 1 day before the study.

Thyroid hormones

At the initial check of the level of thyroid hormones, discontinue drugs that affect thyroid function 2-4 weeks before the test (after agreement with the attending physician). When monitoring treatment, exclude the use of drugs on the day of the study and be sure to note this in the referral form (also note information about taking other drugs – aspirin, tranquilizers, corticosteroids, oral contraceptives).

Sex hormones

In women of reproductive age, the results of hormonal studies are influenced by physiological factors associated with the phase of the menstrual cycle. During the examination for sex hormones, indicate the phase of the menstrual cycle. Hormones of the reproductive system must be given strictly on the days of the cycle:

• LH, FSH – 3-5 day of the cycle;
• Estradiol – 5-7 or 21-23 days of the cycle;
• Progesterone – 21-23 days of the cycle;
• 17-OH-progesterone, DHA sulfate, testosterone – 7-9 days;
• Prolactin – donate blood in the morning at rest, exclude palpation of the mammary glands before the study.

Anti-Müllerian Hormone (AMH/MIS), Inhibin B

For women, the test is performed on days 3-5 of the menstrual cycle. 3 days before blood sampling, exclude intensive sports training. The study should not be performed during any acute illness. Do not smoke for 1 hour before blood sampling.

Adrenaline and norepinephrine

Eliminate drugs: salicylates, β-blockers 8 days before the study. 1 day before the study, it is necessary to refrain from heavy physical activity, exclude alcohol, coffee, tea, B vitamins, bananas.

Renin, angiotensin

Avoid taking estrogens (for 1-2 months), diuretics (for 3 weeks), antihypertensive drugs (for one week) before the study. Blood sampling is carried out in a sitting or standing position.

Aldosterone

In agreement with the doctor, stop antihypertensive drugs, β-blockers, laxatives, corticosteroids, diuretics, antidepressants 8 days before the study. Discontinue aldosterone antagonists 3 weeks prior to study.

ACTH, cortisol

Due to the fact that ACTH and cortisol are stress hormones, it is necessary to calm down and relax for 20 minutes before donating blood. Any stress causes an unmotivated release of these hormones into the blood, which will lead to an increase in this indicator.
The level of these hormones changes cyclically during the day, so the most informative results of studies conducted in the morning before 9 am.

Insulin, C-peptide

Donate blood strictly in the morning.

Gastrin 17, Gastrin-17 stimulated, pepsinogen I, pepsinogen II, H. Pylori IgG

Blood for examination must be taken strictly on an empty stomach after a 12-hour fast.
1 week before the study, refrain from taking drugs that affect gastric secretion: Pepcedin, Zantac, Nizax, Ranimex, Esofex, Losec, Somac, Ranixal, Ranil.
1 day before the study, refrain from taking medications that neutralize hydrochloric acid secreted by the stomach: Alsucral, Balancid, Prepulsid, Metropam, Librax, Gaviscon.
If you have difficulty stopping medication, be sure to tell your doctor.
Refrain from smoking 3 hours before donating blood.

Hemostasis

Protein C, Protein S, von Willebrand factor

Do not test during acute periods of illness and while taking anticoagulant drugs (at least 30 days must elapse after withdrawal). Biomaterial for research must be taken on an empty stomach. At least 8 hours should elapse between the last meal and blood sampling.

Tumor markers

PSA (total, free)

After prostate biopsy and prostate massage, blood for PSA determination can be taken no earlier than 2 weeks later. The post-surgical PSA level is determined no earlier than 6 weeks after the intervention.

Blood tests for infections

Eliminate high-fat foods from the diet 1-2 days before the test. 2 days before donating blood for viral hepatitis, exclude citrus fruits, orange fruits and vegetables from the diet.
The results of tests for infections depend on the period of infection and the state of the immune system, so a negative result does not completely rule out infection. At an early stage of the disease, seroconversion occurs (absence of antibodies in the acute period of the disease).
In doubtful cases, it is advisable to repeat the analysis after 3-5 days.
A blood test for the presence of IgM antibodies to infectious agents should be carried out no earlier than 5-7 days from the moment of illness, and IgG, IgA antibodies no earlier than 10-14 days. This is due to the timing of the production of antibodies by the immune system and their appearance in the blood in the diagnostic titer.

Analysis for enterobiasis

For laboratory testing for enterobiasis, the material of the external print is taken from the perianal folds. The procedure is carried out immediately after sleep, early in the morning, before the act of defecation and washing. The fence is carried out using a plastic transparent spatula with water-based glue applied to it. To do this, it is necessary to push the buttocks apart and attach the sticky side of the spatula to the perianal folds.

After taking the impression, the spatula is placed in the transport container. The label of the container indicates the full name and date. The container with the material is delivered to the laboratory, if necessary, it can be stored for 3 days, in a place protected from light at room temperature (+18 – +22C).

The container for collecting material can be taken in advance at the Laboratory office at the address: Obninsk, st. Aksenova, d. 6a.

Rules for the collection of feces

Before donating the material (3-4 days in advance), it is necessary to stop taking medications (laxatives, castor and vaseline oil, rectal suppositories). It is not allowed to study the feces obtained after an enema or barium intake (during an x-ray examination).

Urinate into the toilet before collecting the sample. Next, by natural defecation in a bedpan (previously washed and dried), collect the stool. Feces are collected in a clean, disposable container, no more than 1/3 of its volume.

The material must be delivered to the laboratory within 3 hours of collection. It is advisable to store the analysis in the cold (+2 … + 8C) during this period, avoiding freezing.

Throat swab

Mouthwashes and throat sprays should be avoided because they kill most of the microbes found in the mucous membrane of the throat and keep their numbers to a minimum. As a result, the analysis, of course, will not show the true number of microbes in the mucosa and those bacteria that can cause or have already caused the disease will not be detected in the smear. It is advisable not to eat or drink at all on the day of the test, and if possible it is better to refuse even a glass of water or a cup of coffee in the morning after waking up. Thus, the bacteria need to be given free rein and allowed to multiply freely in the mucosa for 2-3 days without exposure to various antibacterial agents, and only then can the real picture be seen.

Pap test for women

At least 36 hours must have elapsed since the last intercourse.

If you have been treated with antibiotics, you must first complete the course of treatment and then wait at least 3 weeks before getting tested.

Do not test if women are menstruating or bleeding from the uterus.

Do not wash your face before taking a smear, especially if you use antibacterial soap.

Do not urinate for at least 3 hours before testing. The rule applies to both women and men.

If women have not completed their treatment yet, they take medications, insert vaginal suppositories, they should tell the doctor about this, then it is impossible to take a smear.