What is hematocrit and why is it important. How is a hematocrit test performed. What are the normal ranges for hematocrit in adults and infants. What can cause low hematocrit levels. How does hematocrit relate to overall health and wellness.

What is Hematocrit and Its Significance in Blood Testing?

Hematocrit, often abbreviated as HCT, is a crucial blood test that measures the proportion of red blood cells in a person’s blood volume. This measurement provides valuable insights into an individual’s overall health and can indicate various underlying conditions. But what exactly does hematocrit tell us about our bodies?

Hematocrit is essentially a percentage that represents how much of our blood is composed of red blood cells. These cells are responsible for transporting oxygen throughout the body, making them vital for our survival and well-being. The hematocrit value depends on both the number and size of red blood cells present in the bloodstream.

The Multifaceted Role of Blood in Our Bodies

To fully appreciate the importance of hematocrit, it’s essential to understand the diverse functions of blood in our body:

• Oxygen and nutrient transport to tissues
• Removal of waste products and carbon dioxide
• Distribution of hormones from endocrine organs to target tissues
• Maintenance of body temperature
• Regulation of pH levels in body tissues
• Formation of blood clots to prevent excessive bleeding
• Defense against infections

Given these critical roles, it’s clear why monitoring blood composition through tests like hematocrit is so important for assessing overall health.

How is a Hematocrit Test Performed?

A hematocrit test is a relatively simple and straightforward procedure. But what does it entail? Here’s a breakdown of the process:

1. A blood sample is drawn from the patient, typically from a vein in the arm.
2. The sample is then analyzed in a laboratory setting.
3. No special preparation is required for this test, making it convenient for patients.

While the test itself is simple, many patients wonder about the experience. What does it feel like to have blood drawn for a hematocrit test?

Most people report feeling a moderate amount of pain when the needle is inserted. Some may only experience a slight prick or stinging sensation. After the procedure, there might be some throbbing or a slight bruise at the site of the needle insertion, but this typically subsides quickly.

When and Why is a Hematocrit Test Recommended?

Hematocrit testing is not typically performed in isolation. Instead, it’s usually part of a comprehensive blood panel known as a complete blood count (CBC). But under what circumstances might a healthcare provider recommend this test?

• Signs or risk factors for anemia
• Before and after major surgeries
• Presence of blood in stools or vomit
• Chronic medical conditions like kidney disease or certain types of arthritis
• During pregnancy
• Unexplained fatigue, poor health, or weight loss
• Persistent headaches
• Heavy menstrual periods
• Leukemia or other bone marrow problems
• Monitoring during cancer treatment
• Evaluation of medication side effects that may affect blood counts
• Poor nutrition
• Difficulty concentrating

These diverse scenarios highlight the versatility of hematocrit testing in diagnosing and monitoring various health conditions.

What Are the Normal Hematocrit Ranges?

Understanding what constitutes a “normal” hematocrit level is crucial for interpreting test results. However, it’s important to note that these ranges can vary slightly between different laboratories and testing methods. What are the general guidelines for normal hematocrit levels?

• Adult Males: 40.7% to 50.3%
• Adult Females: 36.1% to 44.3%
• Newborns: 45% to 61%
• Infants: 32% to 42%

It’s worth noting that these ranges are general guidelines. Individual results should always be interpreted by a healthcare professional in the context of the patient’s overall health and other diagnostic information.

What Can Cause Low Hematocrit Levels?

A low hematocrit reading can be indicative of various health issues. But what are the potential causes of a decreased hematocrit count?

• Anemia: A condition characterized by a lack of healthy red blood cells
• Bleeding: Both acute and chronic blood loss can lead to low hematocrit
• Bone marrow dysfunction: Conditions that impair the production of new red blood cells
• Chronic illnesses: Various long-term health conditions can affect hematocrit levels
• Chronic kidney disease: The kidneys play a role in stimulating red blood cell production
• Hemolysis: Premature destruction of red blood cells
• Leukemia: A cancer of blood-forming tissues
• Malnutrition: Inadequate intake of essential nutrients
• Nutritional deficiencies: Particularly iron, folate, vitamin B12, and vitamin B6
• Overhydration: Excessive fluid intake can dilute the concentration of red blood cells

Understanding these potential causes can help healthcare providers pinpoint the underlying issue and develop an appropriate treatment plan.

The Importance of Hematocrit in Diagnosing Anemia

Anemia is one of the most common conditions associated with low hematocrit levels. But how does hematocrit testing help in diagnosing this condition?

Anemia occurs when there aren’t enough healthy red blood cells to carry adequate oxygen to the body’s tissues. A low hematocrit is often one of the first indicators of anemia. However, it’s important to note that hematocrit alone is not sufficient to diagnose anemia. Healthcare providers typically consider hematocrit results alongside other blood tests, such as hemoglobin levels and red blood cell count, to make a definitive diagnosis.

Types of Anemia Detectable Through Hematocrit Testing

Different types of anemia can be indicated by low hematocrit levels:

• Iron-deficiency anemia: The most common type, often due to inadequate iron intake or absorption
• Vitamin-deficiency anemia: Caused by low levels of vitamin B12 or folate
• Aplastic anemia: A rare condition where the body stops producing enough new blood cells
• Hemolytic anemia: Where red blood cells are destroyed faster than they can be replaced
• Sickle cell anemia: An inherited disorder causing abnormally shaped red blood cells

Each of these types of anemia may require different treatment approaches, highlighting the importance of accurate diagnosis through comprehensive blood testing, including hematocrit.

High Hematocrit: Causes and Implications

While low hematocrit levels are more commonly discussed, high hematocrit levels can also indicate health issues. But what can cause an elevated hematocrit count?

• Dehydration: Reduced fluid volume can concentrate red blood cells
• Polycythemia vera: A rare blood cancer that causes the body to produce too many red blood cells
• Chronic obstructive pulmonary disease (COPD): Can lead to increased red blood cell production as a compensation mechanism
• Congenital heart disease: Certain heart defects can result in higher hematocrit levels
• Living at high altitudes: The body produces more red blood cells to compensate for lower oxygen levels
• Smoking: Can increase red blood cell production

High hematocrit levels can increase the risk of blood clots, which may lead to serious complications such as stroke or heart attack. Therefore, it’s crucial to identify and address the underlying cause of elevated hematocrit promptly.

The Role of Nutrition in Maintaining Healthy Hematocrit Levels

Nutrition plays a vital role in maintaining healthy hematocrit levels. But which nutrients are particularly important for red blood cell production and maintenance?

• Iron: Essential for hemoglobin production
• Vitamin B12: Necessary for red blood cell maturation
• Folate: Crucial for DNA synthesis in red blood cells
• Vitamin B6: Involved in heme synthesis
• Copper: Facilitates iron absorption and utilization
• Vitamin A: Supports iron mobilization and use

A balanced diet rich in these nutrients can help maintain healthy hematocrit levels. Foods such as lean meats, fish, leafy green vegetables, legumes, and fortified cereals are excellent sources of these essential nutrients.

Dietary Recommendations for Optimal Hematocrit Levels

To support healthy hematocrit levels through nutrition, consider incorporating these foods into your diet:

• Red meat, poultry, and fish for iron and vitamin B12
• Leafy greens like spinach and kale for iron and folate
• Legumes such as lentils and beans for iron and folate
• Nuts and seeds for copper and vitamin B6
• Citrus fruits for vitamin C, which enhances iron absorption
• Fortified cereals for added vitamins and minerals

Remember, while nutrition is crucial, it’s just one aspect of maintaining healthy hematocrit levels. Regular exercise, adequate hydration, and avoiding harmful habits like smoking are also important factors.

Hematocrit Testing in Pregnancy: Why It’s Crucial

Pregnancy is a time of significant physiological changes, and monitoring hematocrit levels becomes particularly important during this period. But why is hematocrit testing so crucial during pregnancy?

During pregnancy, a woman’s blood volume increases by about 50% to support the growing fetus. However, the increase in red blood cell production doesn’t always keep pace with this plasma volume expansion, leading to a natural decrease in hematocrit levels. This phenomenon is known as physiological anemia of pregnancy.

Importance of Hematocrit Monitoring in Pregnancy

• Detecting true anemia: Distinguishing between physiological anemia and true anemia requiring treatment
• Assessing risk of complications: Low hematocrit can increase the risk of preterm delivery and low birth weight
• Guiding nutritional interventions: Identifying the need for iron or other supplements
• Preparing for delivery: Ensuring adequate red blood cell levels to compensate for blood loss during childbirth

Healthcare providers typically monitor hematocrit levels throughout pregnancy, with testing often performed during the first prenatal visit, again at 28 weeks, and then as needed based on individual circumstances.

Hematocrit in Athletes: Performance and Health Implications

For athletes, particularly those in endurance sports, hematocrit levels can have significant implications for performance and health. But how does hematocrit affect athletic performance, and what should athletes know about their hematocrit levels?

Higher hematocrit levels generally mean a greater oxygen-carrying capacity of the blood, which can enhance endurance and performance. This relationship has led to unethical practices such as blood doping, where athletes artificially increase their red blood cell count to gain a competitive advantage.

Natural Variations in Athlete Hematocrit Levels

Several factors can naturally influence an athlete’s hematocrit levels:

• Training at high altitudes: Can increase red blood cell production
• Intense endurance training: May lead to a temporary decrease in hematocrit due to plasma volume expansion
• Dehydration: Can cause a temporary increase in hematocrit
• Sport-specific adaptations: Some sports may lead to characteristic changes in blood composition

While a higher hematocrit can potentially enhance performance, excessively high levels can also increase the risk of blood clots and other cardiovascular complications. Therefore, athletes and their healthcare providers must carefully monitor hematocrit levels to ensure both optimal performance and health.

The Future of Hematocrit Testing: Advances in Technology and Interpretation

As medical technology continues to advance, the future of hematocrit testing looks promising. But what developments can we expect in this field?

• Point-of-care testing: Rapid, portable devices for immediate hematocrit results
• Non-invasive methods: Technologies that measure hematocrit without blood draws
• Integration with artificial intelligence: AI algorithms to interpret results in context with other health data
• Personalized reference ranges: Tailored normal ranges based on individual factors like age, sex, and ethnicity
• Continuous monitoring: Wearable devices for real-time hematocrit tracking in certain patient populations

These advancements could lead to more frequent, convenient, and personalized hematocrit testing, potentially improving early detection and management of various health conditions.

Challenges and Ethical Considerations

While technological advancements offer exciting possibilities, they also present challenges:

• Ensuring accuracy and reliability of new testing methods
• Protecting patient privacy with increased data collection and analysis
• Addressing potential health disparities in access to advanced testing technologies
• Navigating ethical concerns related to continuous health monitoring

As we move forward, it will be crucial to balance the benefits of these advancements with careful consideration of their broader implications for healthcare and society.

Understanding Hematocrit in the Context of Overall Health

While hematocrit is a valuable diagnostic tool, it’s essential to remember that it’s just one piece of the larger health puzzle. How should we interpret hematocrit results in the context of overall health and wellness?

Hematocrit levels should always be considered alongside other health indicators, including:

• Other blood test results, particularly within the complete blood count
• Physical examination findings
• Patient symptoms and medical history
• Lifestyle factors such as diet, exercise, and stress levels
• Environmental factors like altitude of residence

A holistic approach to health assessment, incorporating hematocrit alongside these other factors, provides a more comprehensive picture of an individual’s health status.

The Importance of Regular Health Check-ups

Regular health check-ups, including hematocrit testing, are crucial for maintaining optimal health. These routine assessments can:

• Detect potential health issues before they become serious
• Track changes in health status over time
• Guide preventive health measures
• Provide peace of mind about one’s health status

By incorporating hematocrit testing into regular health check-ups, individuals can take a proactive approach to their health, potentially preventing or managing conditions before they significantly impact quality of life.

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.

What it is, levels, high and low range

Hematocrit is the percentage of red blood cells in a person’s blood. A typical hematocrit range in healthy adults is 37–52%. This varies depending on a person’s sex and age.

Authors of a 2017 study identified the above typical range.

Low red blood cell levels indicate conditions such as anemia. High red blood cell levels could signal polycythemia, increasing a person’s chance of developing a blood clot.

If a person feels tired, dizzy, or short of breath, a doctor may want to test their hematocrit levels to see if those levels fall into a normal range or not.

Read on to learn more about what this measure of red blood cell volume means, symptoms of abnormal levels, and what low and high levels might indicate.

Hematocrit measures the percentage of red blood cells in the body. For example: if a person has 50 milliliters (ml) of red blood cells in 100 ml of blood, their hematocrit level is 50%.

Red blood cells transport oxygen around the body and give blood its characteristic red color. In addition to oxygen, they also contain hemoglobin, a protein that binds to oxygen molecules. This allows red blood cells to pick up oxygen from the lungs and deliver it throughout the body.

An adequate amount of red blood cells is essential to keep the body’s processes running smoothly.

Many conditions can affect red blood cell production or its life cycle. This can make it difficult for a medical professional to diagnose these conditions. A doctor will use a hematocrit test to confirm whether a person’s red blood cell count is affecting a health condition.

Doctors usually test hematocrit levels as part of a complete blood count (CBC).

A CBC is composed of a range of tests and may include:

• red blood cell count
• reticulocyte count (young red blood cells)
• an analysis of hemoglobin levels
• an analysis of red blood cells, including size and shape
• white blood cell tests
• platelet tests

A doctor will also consider a person’s sex, race, and age. It is important to note that certain blood-related conditions, such as sickle-cell anemia, affect particular demographic groups at higher rates.

Learn more about sickle cell anemia in African Americans here.

A doctor may request frequent hematocrit tests to monitor the effect of chemotherapy on a person’s bone marrow.

Both high and low hematocrit levels can be detrimental to a person’s health and result from various conditions and lifestyle factors.

What are normal hematocrit levels?

Different institutions will define normal hematocrit levels differently. However, a 2017 cross-population study found the following ranges to be typical.

• Male: 42-52%
• Female: 37-47%
• Children: 30–44%, depending on their age and sex

Newborn babies have high hematocrit levels that gradually decrease as they get older.

If a person has recently received a blood transfusion, it may affect their results. Additionally, pregnant individuals may have lower levels than usual because the body increases its blood volume during pregnancy.

Other factors, such as smoking and chronic obstructive pulmonary disease (COPD), may push levels into a higher range.

Low levels

A hematocrit level below 35% in women and 41% in men is low. A level under this value can signify chronic anemia.

High levels

Hematocrit levels above the typical ranges can have adverse effects. It may indicate serious underlying health conditions.

Accuracy of results

Results from hematocrit tests are typically accurate and provide a clear reading of a person’s red blood cell levels.

However, the percentage of red blood cells in someone’s blood can change depending on various lifestyle factors and even environmental changes. According to research, red blood cell counts tend to increase at high altitudes.

Exercise, particularly strength training, may also affect hematocrit levels. A 2018 study found that females who participated in 16 weeks of strength exercise had lower levels at the end than when they started. However, the study had a small sample size of 26 middle-aged, sedentary Turkish women. This means that these findings aren’t necessarily representative of a wider population.

Dehydration can also raise hematocrit levels, so this test is useful if a doctor suspects severe dehydration is the cause of a person’s symptoms.

When a person has low hematocrit levels, they tend to present with the following symptoms:

• pale complexion
• weakness
• fatigue
• low energy
• trouble breathing
• irregular heartbeat
• cold hands or feet

These symptoms also indicate anemia, a condition where hemoglobin levels are lower than normal. Hemoglobin is a protein found in red blood cells that carries oxygen around the body.

Mild anemia is treatable, and it is particularly common in women. Severe anemia could signal a more serious underlying health condition that requires more extensive treatment.

Doctors associate anemia with several health conditions, including:

Nutrient deficiency

A person may lack B12, folate, or iron in their diet.

Learn more about how nutrient deficiency anemia is diagnosed and treated.

Chronic bleeding

This commonly occurs due to digestive tract ulcers, which are sores caused by the bacteria H.pylori or chronic use of anti-inflammatory medications such as ibuprofen, other nonsteroidal anti-inflammatory drugs (NSAIDs), and aspirin. Many women also experience excessive blood loss from heavy menstrual bleeding.

Bone marrow disorder

This includes aplastic anemia, which damages stem cells in bone marrow.

Cancer

These cancers spread to bone marrow, such as leukemia and lymphoma.

Learn more about bone marrow cancers here.

Kidney failure

Kidney disease can lower the production of red blood cells, reducing hematocrit levels.

Thalassemia

When a person has this condition, their body does not produce enough hemoglobin.

Learn more about thalassemia here.

Sickle cell anemia

This condition changes the shape of red blood cells. These cells die earlier than normal, and they also clump together, which impairs blood flow.

Learn more about sickle cell anemia here.

Autoimmune disease

Conditions like rheumatoid arthritis and lupus may reduce red blood cell count.

Learn more about autoimmune diseases here.

When a person has high hematocrit levels, they tend to present with these symptoms:

• flushed skin
• dizziness
• vision problems
• headaches
• enlarged spleen

These symptoms signal polycythemia, a condition where the body produces too many red blood cells. This means blood is thicker and clots more easily.

Doctors cannot cure polycythemia, so treatment focuses on symptom management. The main goal is to avoid stroke and deep vein thrombosis (DVT), which is a blood clot usually occurring in a deep vein in the leg.

In some cases, dehydration causes polycythemia. When a person does not drink enough, their plasma levels drop, increasing the proportion of red blood cells in their blood volume. A person can lower their red blood cell count by rehydrating.

Some conditions that can cause high hematocrit levels include:

Lung or pulmonary disease

When the lungs cannot absorb oxygen effectively, and oxygen levels drop, the body compensates by making more red blood cells. One common pulmonary disease causing this is COPD.

Learn more about COPD here.

Heart disease

If the structure of a person’s heart reduces its ability to pump blood around the body, it can no longer sustain vital organs with oxygen. To try and overcome the oxygen deficit, the body produces more red blood cells.

Learn more about heart disease here.

Kidney cancer

Sometimes kidney cancer cells create more erythropoietin. Erythropoietin is a hormone that tells the bone marrow to create more red blood cells.

Learn more about kidney cancer here.

Genetic disease

The JAK2 gene, which controls the number of blood cells made in the bone marrow, can affect certain conditions. When someone has a mutated JAK2 gene, the body could make a protein that signals the bone marrow to create more red blood cells than it needs.

Learn more about genetic disorders here.

A person should speak with a doctor if they are experiencing any of the symptoms listed above that could be a sign of high or low hematocrit levels, including fatigue, weakness, vision problems, and dizziness.

These symptoms can also indicate an underlying condition, so a person must contact a doctor promptly to prevent future complications.

If a person is receiving chemotherapy treatment, a doctor should perform regular hematocrit tests to monitor bone marrow health.

Hematocrit is the percentage of blood cells in a person’s blood volume. A doctor may test an individual’s hematocrit level due to certain symptoms.

A low hematocrit level means there are too few red blood cells in the body. In these cases, a person may experience symptoms that signal anemia. Common symptoms include fatigue, weakness, and low energy.

If a person has too many red blood cells, they have a high hematocrit level. A person may experience dizziness and headaches, which can be a sign of the condition polycythemia.

Demographic and lifestyle factors can influence a person’s hematocrit levels. For example, males tend to have higher levels than females. Pregnant individuals can experience a decrease in hematocrit levels, and strength training may also reduce levels.

There are also several health conditions that can cause hematocrit levels outside the normal range. Excessive bleeding, thalassemia, and kidney disease are causes of low levels. COPD and sickle cell anemia can cause high levels.

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norm in a child, women, men, causes of increased, decreased values ​​in the blood

Hematocrit is one of the blood indicators that registers the total volume of all formed elements, and these are erythrocytes, leukocytes and platelets, in relation to the total volume. Moreover, 99% of the volume of all these elements falls on erythrocytes. The hematocrit (Ht) is expressed as a percentage, but a liter per liter (L/L) can also be selected.

Human blood contains from 36 to 48% of formed elements, it also contains plasma, water, proteins, carbohydrates and salts.

Hematocrit is determined simply: a certain amount of blood is poured into a special tube with graduation, then it is sent to a centrifuge, and at the end of the process, the fraction of the length of the tube that was filled with erythrocyte mass is determined. Also, laboratories now use automatic hematology analyzers that allow you to get data in just a few minutes.

Blood hematocrit norm

The body of an adult healthy person contains about 5 liters of blood. Erythrocytes, leukocytes and platelets cannot be called cells, they do not have the necessary parameters for this. Therefore, they are called formed elements. Different people have different amounts of these elements per liter of blood. For example, according to statistics, the hematocrit in men is higher and equal to 40-41%, sometimes this figure can reach 51%.

Hematocrit in women is slightly lower and usually ranges from 36-42%. The reason for this is such a physiological feature as menstruation. As for the period of pregnancy, here this figure begins to decrease in the second half, and this is also not a pathology.

Hematocrit in children always depends on age, therefore, before drawing conclusions from the analysis, it is necessary to find out how many months or years the baby is. In newborn babies, this figure can be equal to 44-62%, at the age of 3 months it decreases and the figure becomes up to 44%, from 3 months to 1 year the figures can range from 32 to 43%. In the first ten years, Ht in boys can rise to 52%, and in girls it can be at around 35-47%. In subsequent years, the hematocrit norm is equal to the same indicator that is recorded in adults.

Causes of increased hematocrit

Why can it happen that the hematocrit in the blood test is elevated? There are pathological and physiological causes, so before starting any treatment, it is important to understand their origin.

Pathological causes include the following diseases and conditions:

1. Dehydration (dehydration). Due to the fact that the amount of blood that circulates through the vessels decreases, the formed elements are in a more concentrated state. This happens with vomiting, diarrhea, heavy sweating, overheating, lack of fluid.
2. Second and third degree burns. In this case, blisters appear on the body, which are filled with plasma, and it appeared in them from the bloodstream. Therefore, the blood becomes thicker, and the concentration of formed elements increases.
3. Peritonitis, thrombosis or diabetes mellitus.
4. Chronic hypoxia.
5. Regular use of glucocorticosteroids or diuretics.
6. Kidney disease – hydronephrosis.
7. Almost all blood diseases, including leukemia.
8. Polycystic.
9. Heart defects, ischemic heart disease.
10. Erythremia.
11. Many lung diseases, including asthma, bronchitis.
12. Severe bleeding.

However, hematocrit analysis alone is not enough to make an accurate diagnosis, it is not very informative. Therefore, it is often done as part of a general blood test, and further therapy tactics are already built on it, if it turns out to be necessary.

But elevated hematocrit can also be the result of certain physiological phenomena. In this case, deviations of this indicator cannot be considered pathological. High Ht in comparison with the norm is detected in people who smoke constantly and for a long time, which is associated with the development of chronic oxygen starvation of tissues and increased production of red blood cells.

Residents of high mountain regions and mountaineers who spend a lot of time at altitude also have Ht in the range of 51-52%. This is all connected with the same oxygen starvation and the need for the body to compensate for this lack. Also, elevated Ht is typical for athletes who take anabolics that help them gain the required amount of muscle mass.

Manifestations and symptoms of elevated hematocrit

If the hematocrit in the blood is elevated, then this will not necessarily be expressed by certain symptoms. However, it should be remembered that this condition is always expressed by an increase in blood viscosity, which creates a great threat for the formation of blood clots and clogging of both small and large vessels.

If this happens in the coronary arteries, then myocardial infarction develops against the background of thrombosis. If a thrombus forms in the pulmonary artery, then death occurs in 70% of all cases. If the arteries of the brain are affected, then this leads to the development of an ischemic stroke. With thrombosis of the vessels of the legs, gangrene begins to develop.

Therefore, it is important to find out the cause of elevated Ht as soon as possible and start timely treatment.

Reasons for low hematocrit

A decrease in hematocrit can occur without any pronounced symptoms, so this result is usually detected after a blood test and is an unexpected discovery for a person.

The main reasons why the hematocrit may be low are:

• virtually all anemias, including iron deficiency, folate deficiency, B12 deficiency;
• violation of the production of red blood cells due to pathologies of the bone marrow, including oncological ones;
• cirrhosis of the liver;
• diseases of the urinary system;
• hemolysis or destruction of red blood cells;
• chronic bleeding;
• increase in circulating blood volume;
• hyperproteinemia;
• lead intoxication;
• acute infections;
• the use of anticoagulants and similar drugs that affect the composition of the blood.

Decreased hematocrit may have physiological causes. This is work associated with a long stay in one position, starvation or adherence to strict diets, a large amount of fluid that enters the body, alcoholism, the use of large amounts of salt, the period of menstruation.

Manifestations and symptoms of low hematocrit

The reasons for the drop in hematocrit will directly affect what symptoms a person experiences. For example, if it is anemia, then there will be such complaints:

• headache and constant weakness;
• impaired consciousness and breathing;
• dizziness, nausea or vomiting;
• constant thirst;
• lack of strength and exercise intolerance.

If the cause is kidney and urinary system diseases, then there will be complaints about a decrease in the amount of urine excreted, pain in the lumbar region, urination disorder, and changes in blood pressure.

With cirrhosis of the liver, complaints will be of pain in the right side of the abdomen under the ribs, the appearance of spider veins on the skin, indigestion, excessive formation of gases, a feeling of fullness in the abdomen, in advanced cases – internal bleeding.

What tests are needed?

To find out the relative content of all formed elements in the blood, it is necessary to analyze the hematocrit. It is done as part of a general blood test (CBC), when, together with Ht, the number of all elements is calculated, and the ESR is also determined.

Usually, it is with the KLA that a patient’s examination begins to identify a particular disease, or it is carried out for preventive purposes as part of a medical examination, medical examination.

Both venous blood and capillary fingerstick blood can be used for analysis. It is best to take the test in the morning, before breakfast. This allows you to get the right readings that will help the doctor determine if Ht is elevated or low, or its values ​​are within the normal range.

Hematocrit

Hematocrit is the ratio of the volume of erythrocytes to the volume of the liquid part of the blood.

Determination of hematocrit is an integral part of the general blood test and is not performed separately.

Synonyms Russian

Hematocrit value.

Synonyms English

Ht, Hct, Hematocrit, Crit, Haematocrit, PCV, Packed Cell Volume.

Units

% (percentage).

What biomaterial can be used for research?

Venous blood.

General information about the study

Hematocrit determines the amount of blood occupied by red blood cells in the bloodstream. This indicator is expressed as a percentage. For example, a hematocrit of 45% means that 100 milliliters of blood contains 45 milliliters of red blood cells.

An increase in hematocrit occurs if the number of red blood cells increases or the volume of the liquid part of the blood decreases, which happens when the body loses excess fluid (for example, with diarrhea). A decrease in this indicator is observed, on the contrary, with a decrease in the number of red blood cells (for example, due to their loss, destruction, or a decrease in their formation) or with overhydration – when a person receives too much fluid (for example, with excessive administration of intravenous solutions).

Hematocrit reflects not only the number of red blood cells, but also their size. If the size of red blood cells decreases (as in iron deficiency anemia), the hematocrit will also decrease.

What is research used for?

• In the diagnosis of anemia and polycythemia and to evaluate the effectiveness of their treatment.
• To determine the degree of dehydration.
• As one of the criteria for deciding on the need for a blood transfusion.
• To evaluate the effectiveness of blood transfusions.

When is the examination scheduled?

This test is part of a routine complete blood count, which is performed both routinely and in various diseases and pathological conditions, before surgical interventions.

In addition, it can be carried out repeatedly and at certain intervals:

• with dynamic monitoring and evaluation of the effectiveness of the treatment of anemia and polycythemia,
• after conditions causing dehydration,
• for recurrent bleeding for a comprehensive assessment of their severity.

What do the results mean?

Reference values ​​

Generally, the hematocrit corresponds to the number of red blood cells, but this is only true when the size of the red blood cells is normal. If the number of normal-sized red blood cells increases, the hematocrit also rises. In cases of large or small erythrocytes, this is not always the case. For example, with iron deficiency, red blood cells decrease and the hematocrit will be reduced, but the number of red blood cells per unit of blood may be normal and even slightly higher.

Hematocrit level above 55% requires clarification of the cause and further diagnostic search.

Causes of low hematocrit:

• iron-, B ₁₂ – or folic deficiency anemia,
• acute or chronic bleeding (during or immediately after bleeding, hematocrit and hemoglobin will be elevated),
• disorders of hemoglobin synthesis (sickle cell anemia, thalassemia),
• cirrhosis of the liver,
• destruction of erythrocytes as a result of hemolysis – destruction of erythrocytes inside the body (it can occur for various reasons – due to a hereditary defect in erythrocytes, as a result of the appearance of antibodies to one’s own erythrocytes or toxic effects in malaria),
• oncological diseases of the bone marrow or metastases of other tumors in the bone marrow, leading to a decrease in the synthesis of red blood cells,
• excessive hydration of the body – the introduction of large volumes of intravenous fluids.

Causes of increased hematocrit:

• dehydration (dehydration) of any origin – due to diarrhea, profuse vomiting, diabetes, after burns,
• polycythemia vera due to excessive production of red blood cells in the bone marrow,
• chronic obstructive pulmonary disease,
• chronic heart failure.

What can influence the result of ?

1. The hematocrit level is normally reduced in pregnant women due to a physiological increase in the volume of the liquid part of the blood.
2. Persons ascending to high altitudes experience an increase in the number of red blood cells and, consequently, hematocrit, as their body adapts to the reduced oxygen concentration.
3. Hematocrit may be increased in smokers due to oxygen deprivation of tissues and increased production of red blood cells.
4. In newborns, the hematocrit level is increased, since they have quite a lot of large red blood cells in their blood.