What is a hematocrit test? How is it performed? What do the results mean? Find answers to these questions and more in our comprehensive guide on the hematocrit test.

Understanding the Hematocrit Test

The hematocrit (HCT) test is a commonly performed blood test that measures the percentage of red blood cells in a person’s blood. This measurement provides valuable insights into the overall health and functioning of the body’s circulatory system.

The Role of Blood in the Body

Blood plays a crucial role in the body, transporting oxygen and nutrients to tissues, while also removing waste and carbon dioxide. It helps maintain body temperature, pH levels, and supports the immune system’s protective functions, such as clot formation and infection prevention.

How is the Hematocrit Test Performed?

The hematocrit test is typically performed as part of a complete blood count (CBC) procedure. A small sample of blood is drawn from the patient, and the percentage of red blood cells in the sample is determined.

Preparing for the Hematocrit Test

No special preparation is required for the hematocrit test. Patients can typically undergo the test without any changes to their normal routine or diet.

What to Expect During the Test

When the needle is inserted to draw blood, some patients may feel moderate pain, while others may only experience a slight prick or stinging sensation. After the test, there may be some minor throbbing or a slight bruise, which typically goes away quickly.

Interpreting Hematocrit Test Results

Normal hematocrit levels vary depending on age and gender. For adults, the typical range is 40.7% to 50.3% for males and 36.1% to 44.3% for females. Abnormal results may indicate various medical conditions, such as anemia, bleeding, bone marrow disorders, or chronic illnesses.

Reasons for Performing the Hematocrit Test

Hematocrit tests are often ordered as part of a routine checkup or when a healthcare provider suspects a patient may be at risk for anemia or other blood-related conditions. Common reasons for ordering the test include monitoring during surgery, pregnancy, or cancer treatment, as well as investigating symptoms like fatigue, headaches, or unexplained weight loss.

What is the purpose of a hematocrit test?

The primary purpose of a hematocrit test is to measure the percentage of red blood cells in a person’s blood. This information provides insights into the overall health and functioning of the body’s circulatory system.

How is the hematocrit test performed?

The hematocrit test is typically performed as part of a complete blood count (CBC) procedure. A small sample of blood is drawn from the patient, and the percentage of red blood cells in the sample is determined.

What do normal hematocrit results mean?

Normal hematocrit levels vary depending on age and gender. For adults, the typical range is 40.7% to 50.3% for males and 36.1% to 44.3% for females. These values indicate a healthy balance of red blood cells in the blood.

What can abnormal hematocrit results indicate?

Abnormal hematocrit results, either high or low, can be a sign of various medical conditions, such as anemia, bleeding, bone marrow disorders, or chronic illnesses. Low hematocrit may indicate anemia, while high hematocrit can be a sign of dehydration or certain blood disorders.

When might a healthcare provider order a hematocrit test?

Healthcare providers may order a hematocrit test as part of a routine checkup, or when they suspect a patient may be at risk for anemia or other blood-related conditions. Common reasons include monitoring during surgery, pregnancy, or cancer treatment, as well as investigating symptoms like fatigue, headaches, or unexplained weight loss.

How can the hematocrit test help in monitoring and treating medical conditions?

The hematocrit test can provide valuable information for healthcare providers to monitor and manage various medical conditions. By tracking changes in a patient’s hematocrit levels over time, providers can better understand the progression of conditions like anemia, cancer, or kidney disease, and adjust treatment plans accordingly.

Hematocrit Information | Mount Sinai

HCT

Hematocrit is a blood test that measures how much of a person’s blood is made up of red blood cells. This measurement depends on the number of and size of the red blood cells.

Blood transports oxygen and nutrients to body tissues and returns waste and carbon dioxide. Blood distributes nearly everything that is carried from one area in the body to another place within the body. For example, blood transports hormones from endocrine organs to their target organs and tissues. Blood helps maintain body temperature and normal pH levels in body tissues. The protective functions of blood include clot formation and the prevention of infection.

How the Test is Performed

A blood sample is needed.

How to Prepare for the Test

No special preparation is necessary for this test.

How the Test will Feel

When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging. Afterward, there may be some throbbing or a slight bruise. This soon goes away.

Why the Test is Performed

The hematocrit is almost always done as part of a complete blood count (CBC).

Your health care provider may recommend this test if you have signs of or are at risk for anemia. These include having:

• Before and after major surgery
• Blood in your stools, or vomit (if you throw up)
• Chronic medical problems, such as kidney disease or certain types of arthritis
• During pregnancy
• Fatigue, poor health, or unexplained weight loss
• Headaches
• Heavy menstrual periods
• Leukemia or other problems in the bone marrow
• Monitoring during treatment for cancer
• Monitoring medicines that may cause anemia or low blood counts
• Monitoring of anemia and its cause
• Poor nutrition
• Problems concentrating

Normal Results

Normal results vary, but in general they are:

• Male: 40. 7% to 50.3%
• Female: 36.1% to 44.3%

For babies, normal results are:

• Newborn: 45% to 61%
• Infant: 32% to 42%

The examples above are common measurements for results of these tests. Normal value ranges vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your provider about the meaning of your specific test results.

What Abnormal Results Mean

Low hematocrit may be due to:

• Anemia
• Bleeding

• Bone marrow being unable to produce new red blood cells. This may be due to leukemia, other cancers, drug toxicity, radiation therapy, infection, or bone marrow disorders 

• Chronic illness
• Chronic kidney disease
• Destruction of red blood cells (hemolysis)
• Leukemia
• Malnutrition
• Too little iron, folate, vitamin B12, and vitamin B6 in the diet
• Too much water in the body

High hematocrit may be due to:

• Bone marrow disease that causes abnormal increase in red blood cells (polycythemia vera)
• Congenital heart disease
• Exposure to high altitude
• Failure of the right side of the heart
• Low levels of oxygen in the blood
• Scarring or thickening of the lungs
• Too little water in the body (dehydration)

Risks

There is little risk involved with having your blood taken. Veins and arteries vary in size from one person to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.

Other risks associated with having blood drawn are slight but may include:

• Excessive bleeding
• Fainting or feeling lightheaded
• Multiple punctures to locate veins
• Hematoma (blood buildup under the skin)
• Infection (a slight risk any time the skin is broken)

Chernecky CC, Berger BJ. H. Hematocrit blood. In: Chernecky CC, Berger BJ, eds. Laboratory Tests and Diagnostic Procedures. 6th ed. St Louis, MO: Elsevier Saunders; 2013:620-621.

Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM. Blood disorders. In: Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Textbook of Pediatrics. 21st ed. Philadelphia, PA: Elsevier; 2020:chap 124.

Means RT. Approach to the anemias. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 149.

Vajpayee N, Graham SS, Bem S. Basic examination of blood and bone marrow. In: McPherson RA, Pincus MR, eds. Henry’s Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 31.

Last reviewed on: 1/9/2022

Reviewed by: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

Hematocrit | Sight Diagnostics

Definition, Test, Low vs High Levels and Causes

What is hematocrit

Hematocrit (HCT) is the calculated volume percentage of red blood cells (erythrocytes) in your blood. Hematocrit is also called packed cell volume (PCV) or erythrocyte volume fraction.

Human blood contains red blood cells, white blood cells, and platelets suspended in a liquid called plasma. The word hematocrit means to separate blood. In a hematocrit test, the red blood cells are separated from the rest of your blood cells and plasma.

Hematocrit is important because red blood cells are essential to your survival. They contain a vital protein component called hemoglobin that binds to oxygen, which fuels all the cells in your body.

When red blood cells pass through your lungs, they bind to and transport oxygen to various cells in your body. On their way back to your lungs, they carry carbon dioxide to be exhaled. Hematocrit is a significant measurement as it can identify whether you have sufficient red blood cells for oxygen transportation and delivery.

If your doctor suspects that you have a blood disorder such as anemia or polycythemia (too many red blood cells), your doctor may order a hematocrit test to check your red blood cells.

How to measure hematocrit with a test?

The original method for hematocrit measurement is the macrohematocrit (Wintrobe hematocrit tube) method.

It uses a narrow glass tube and a centrifuge machine. The centrifuge separates the blood into three main layers: red blood cells, white blood cells, and platelets, in that order from the bottom up. At the very top, there’s a small layer of blood plasma. The macrohematocrit method carries the risk of measuring trapped plasma as part of the red blood cell layer, which erroneously elevates the hematocrit percentage.[1]

A newer method is the microhematocrit method, which uses a capillary tube instead of a narrow glass tube and requires a smaller quantity of blood and less time. The microhematocrit method traps less plasma because the diameter of the capillary tube is smaller than the Wintrobe hematocrit tube. So the percentage of hematocrit is more accurate in the microhematocrit method than in the macrohematocrit method. [1:1]

Both procedures require the technician to manually measure the length of the layers. The technician calculates hematocrit as the length of the packed red blood cell layer divided by the length of total cells and plasma. This ratio is then multiplied by 100 to give a certain percentage.

Today, these two methods have been largely succeeded by an automated hematology analyzer where the hematocrit test is obtained as part of a complete blood count (CBC) laboratory test. The hematocrit is calculated indirectly from the average volume and the number of red blood cells.[2] The automated analyzer is the fastest method. However, automated analyzers may not be available in areas where resources are low.

In the microhematocrit method, a technician only needs a small sample of blood from a finger-prick. In the other methods, the technician draws blood from the inner side of your arm or the back of your hand. Before drawing blood for the measurement, the technician first cleans the surface from where your blood would be drawn. Next, using a needle, the technician draws your blood. Afterward, the technician covers the surface with gauze and a bandage.

What is a normal hematocrit level?

Due to differences in age and gender, the normal hematocrit is a range. Hematocrit results are reported as a percentage. The average hematocrit measurement for human beings is 45%, which means that the red cell volume contains 45 mL per 100 mL of blood.[3]

According to the Cleveland clinic, the general normal ranges for hematocrit are[4]:

• Male: 41% to 50%
• Female: 36% to 44%
• Newborn: 45% to 61%
• Infant: 32% to 42%

What does it mean if your hematocrit is high?

If your hematocrit is high, it means that you have more red blood cells than is considered healthy. 

High hematocrit may be caused by [4:1]:

• Heart disease
• Dehydration
• Scarring or thickening of the lungs
• Bone marrow disease
• Obstructive sleep apnea
• Smoking and chronic obstructive pulmonary disease (COPD)
• Carbon monoxide poisoning
• Testosterone use

A false high hematocrit may be reported if the patient has cryoproteins, significant leukocytosis, or giant platelets. Hematocrit measurement is critically high if it is greater than 67% (>67%).

What does it mean if your hematocrit is low?

If your hematocrit is low, it means that you have fewer red blood cells than is considered healthy.

Low hematocrit may be caused by[4:2]:

• Blood loss
• Leukemia or other bone marrow problems
• Iron and vitamin deficiency, including folate, vitamin B12, and vitamin B6
• Too much water in the body
• Kidney disease
• Thyroid abnormality
• Immune destruction of red blood cells

A false low hematocrit may be reported if the patient has microcytosis, in vitro hemolysis, or autoagglutinins. Hematocrit is considered critically low if it falls below 21% (<21%).

How to increase hematocrit?

In some cases, hematocrit is caused because of low iron levels. You can eat iron-rich foods and take a daily vitamin supplement to help prevent low hematocrit causes.

Food sources that are rich in iron include:

• Red meat
• Beef liver
• Chicken liver
• Fish and shellfish
• Soy products (tofu and edamame)
• Dried fruit
• Green leafy vegetables
• Nuts
• Beans
• Iron-fortified bread and cereals
• Eggs

Additionally, vitamin C helps with iron absorption. Therefore, also eat various foods that are rich in vitamin C, for example, citrus fruits. Do not drink coffee or tea with your meals because this decreases iron absorption.

Discover Sight’s Automated Hematology Analyzer

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Laboratory tests – Medical Center “Nadezhda” named after. A.S. Aronovich.

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Any laboratory test gives the doctor additional information to help diagnose and prescribe treatment.

The result of any analysis may contain human or hardware error. Therefore, doctors, in addition to the main tests, prescribe confirmatory or clarifying tests. For example, when diagnosing infections, it is desirable not only to analyze the pathogen (seeding or DNA diagnostics), but also to determine the body’s response to this pathogen (enzyme-linked immunosorbent assay – ELISA, component binding reaction). Therefore, full-fledged laboratory diagnostics implies a specific list (standard) of tests for each disease.

Pre-registration is not required for testing.

How to pass tests for a child and an adult?

To tell you about the details of preparing for the collection of all existing analyzes, you will have to write a thick reference book. Therefore, we confine ourselves to the “main” analyzes, which we pass more often than others.

General rules for donating blood

• blood test is taken strictly on an empty stomach – not earlier than 12 hours after the last meal. Dinner the day before should be light and early, and the entire previous day should refrain from fatty foods;
• any alcohol, thermal procedures (bath and sauna) and physical activity are excluded for 24 hours;
• tests are given before x-rays, injections, massage and medication;
• if repeated examinations are necessary, it is advisable to take blood samples at the same time of day;
• Rest for 5-10 minutes in front of the laboratory door.

When donating blood for glucose , in addition, you should not brush your teeth and chew gum, and morning tea or coffee (even unsweetened) is completely contraindicated. Contraceptives, twenty drops of cognac in evening tea, diuretics and other medicines will also change glucose levels.

Biochemical blood tests

In the study of bile pigments, the picture is distorted by products that cause coloring of blood serum – pumpkin, beets, carrots, citrus fruits. Pork chop the day before will increase the level of potassium and uric acid in the blood.

Blood donation for hormones

Stop all hormonal preparations a month before the examination. When donating blood to determine the level of sex hormones, you will also have to refrain from sex (in any form) and sexual arousal for at least 24 hours. Otherwise, at best, you will have to retake an expensive analysis, and at worst, receive inadequate therapy.

Thyroid hormone testing requires avoiding iodine preparations and avoiding iodized salt.

Complete urinalysis

General clinical urinalysis is the most common analysis in medical practice, along with the general blood test. But, despite this, most patients are not aware that before you write in a jar, you need to wash the external genitalia (necessarily towards the anus, and not away from it) and wipe dry with a clean linen napkin. Further, the first and last portions of urine are drained past the container, and medium for clean dishes . Otherwise, bacteria and mucus with leukocytes from the genitals will enter the urine, and the patient will be treated, for example, for pyelonephritis.

Neglect of hygiene or use of dirty dishes is the cause of the most common errors in urinalysis results.

It is also not recommended to collect urine during menstruation. But if you really need it, then a tampon and a thorough shower come to the rescue.

As with a blood test, you need to adjust your diet and stop taking medication. After some drugs or products (for example, beets, vitamins), the color of the urine changes (who will tell the laboratory assistant about this?), And alcohol is categorically contraindicated 24 hours before the analysis.

For general urinalysis use the first morning portion of urine (previous urination should be no later than 4-6 hours). Even if you forget to pee in a jar for the twentieth time when you wake up, you can’t fill it in the evening, otherwise the results will surprise not only you, but also the doctors.

If the patient, when passing the test, did everything that depended on him, then it’s up to the laboratory. And we must not forget that the result of the analysis is not a diagnosis of , it can only be established by the attending physician, comparing the patient’s complaints with clinical data and test results.

In the medical center “Nadezhda” you can always take tests for a child and an adult and get the results in the shortest possible time.

LLC “ECO-MED-S M” – complex equipping of laboratories with modern equipment in medical and scientific institutions. |OOO “ECO-MED-S M”

The EXIAS e1 analyzer is designed for the quantitative determination of electrolytes (Na+, K+, Cl-, Ca2+), pH in whole blood, serum, plasma, dialysis solution and aqueous solutions, and hematocrit (Hct ) in whole blood.

The analyzer is maintenance-free and has exceptional performance. Combines high accuracy and ease of use.
User manipulations are reduced to one step – inserting the cartridge into the analyzer (all in one cartridge system).

Universal cartridge includes:

• sensors, solutions, waste collection and quality control (optional)
• all wearing parts such as tubes, sample injection unit, valves, etc.

With its robust and compact design, the EXIAS e|1 is well suited for both point-of-care and laboratory applications

Specifications

• Built-in printer, barcode reader (optional)
• Data exchange with the laboratory information system in accordance with the protocol LIS2-A2 (ASTM)
• Network connection via LAN connector (RJ45) or WiFi adapter (optional)

Downloads

• RZN 2022-16823 Analyzer e1

• DS as of 17.