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 blood function.

What is Hematocrit and Its Significance in Blood Health

Hematocrit 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 blood health and can indicate various underlying conditions. The hematocrit value depends on both the number and size of red blood cells present in the bloodstream.

Red blood cells play a vital role in the body’s functioning. They are responsible for:

• Transporting oxygen and nutrients to body tissues
• Removing waste products and carbon dioxide
• Distributing hormones from endocrine organs to target tissues
• Maintaining body temperature and pH levels
• Assisting in clot formation and infection prevention

Given the importance of red blood cells, monitoring hematocrit levels can provide critical information about a person’s health status and potential blood-related disorders.

The Hematocrit Test: Procedure and Preparation

How is a hematocrit test conducted? The procedure is relatively simple and requires a blood sample. A healthcare professional will draw blood from a vein, typically in the arm, using a needle. This sample is then analyzed in a laboratory to determine the hematocrit level.

Do patients need to prepare for a hematocrit test? Fortunately, no special preparation is necessary for this test. It can be performed at any time of day, and fasting is not required. However, it’s essential to inform your healthcare provider about any medications or supplements you’re taking, as these may affect the results.

What to Expect During the Test

While the hematocrit test is a routine procedure, it’s natural to have some concerns about the process. Here’s what you can expect:

• You may feel a brief sting or pinch when the needle is inserted
• Some individuals experience moderate pain, while others only feel a slight prick
• After the blood draw, you might notice some throbbing or a small bruise at the site
• Any discomfort typically subsides quickly

If you have a history of feeling faint during blood draws, inform your healthcare provider beforehand so they can take appropriate precautions.

Normal Hematocrit Ranges: What Do They Mean?

Understanding normal hematocrit ranges is crucial for interpreting test results. These ranges can vary slightly between laboratories, but generally, they are as follows:

• Adult males: 40.7% to 50.3%
• Adult females: 36.1% to 44.3%
• Newborns: 45% to 61%
• Infants: 32% to 42%

Why do hematocrit levels differ between males and females? This variation is primarily due to the influence of hormones on red blood cell production. Testosterone, which is present in higher levels in males, stimulates red blood cell production, resulting in slightly higher hematocrit levels in men compared to women.

Is it normal for newborns to have higher hematocrit levels? Yes, newborns typically have higher hematocrit levels than adults. This is because they need extra red blood cells to help them transition from the womb to the outside world, where oxygen levels are different.

Causes of Low Hematocrit: Unraveling the Possibilities

A low hematocrit count can be indicative of various health issues. Some common causes include:

1. Anemia: A condition characterized by a lack of healthy red blood cells
2. Bleeding: Both acute and chronic blood loss can lead to low hematocrit
3. Bone marrow disorders: Conditions that affect the production of new red blood cells
4. Chronic illnesses: Such as kidney disease or certain types of arthritis
5. Nutritional deficiencies: Particularly iron, folate, vitamin B12, and vitamin B6
6. Leukemia: A cancer of blood-forming tissues
7. Hemolysis: The destruction of red blood cells faster than they can be replaced
8. Overhydration: Excessive fluid in the body can dilute the concentration of red blood cells

How can you determine the specific cause of low hematocrit? Your healthcare provider will consider your hematocrit results alongside other blood tests, your medical history, and any symptoms you’re experiencing to make an accurate diagnosis.

When is a Hematocrit Test Recommended?

Healthcare providers may recommend a hematocrit test in various situations. Some common reasons include:

• Symptoms of anemia (fatigue, weakness, pale skin)
• Unexplained weight loss or poor health
• Chronic medical conditions
• Monitoring during pregnancy
• Before and after major surgeries
• Evaluation of heavy menstrual periods
• Monitoring cancer treatments
• Assessment of medications that may affect blood counts
• Investigation of blood in stools or vomit
• Persistent headaches or concentration problems

Is a hematocrit test always performed alone? Typically, hematocrit is measured as part of a complete blood count (CBC), which provides a comprehensive overview of blood cell components and characteristics.

The Impact of High Hematocrit: Understanding the Risks

While low hematocrit levels are more commonly discussed, high hematocrit levels can also indicate health issues. Elevated hematocrit may be caused by:

• Dehydration: Reduced fluid in the blood concentrates red blood cells
• Polycythemia vera: A rare blood disorder causing overproduction of red blood cells
• Lung diseases: Conditions that reduce oxygen levels in the blood
• Heart diseases: Particularly those affecting the right side of the heart
• Living at high altitudes: The body produces more red blood cells to compensate for lower oxygen levels
• Certain medications: Such as anabolic steroids or erythropoietin

What are the potential risks of high hematocrit? Elevated levels can increase blood viscosity, potentially leading to clot formation, stroke, or heart attack. If you have high hematocrit, your healthcare provider will work to identify and address the underlying cause.

Hematocrit and Overall Health: Connecting the Dots

Hematocrit levels serve as a window into your overall health, offering insights into various bodily functions. Here’s how hematocrit relates to different aspects of health:

Oxygen Delivery

Red blood cells are crucial for oxygen transport. A low hematocrit can result in reduced oxygen delivery to tissues, leading to fatigue, shortness of breath, and decreased physical performance.

Nutritional Status

Hematocrit levels can reflect your nutritional status, particularly in terms of iron, vitamin B12, and folate. Low levels may indicate deficiencies in these essential nutrients.

Chronic Disease Management

For individuals with chronic conditions like kidney disease or certain types of cancer, regular hematocrit monitoring can help assess disease progression and treatment effectiveness.

Cardiovascular Health

Both low and high hematocrit levels can impact cardiovascular health. Low levels may strain the heart as it works harder to deliver oxygen, while high levels can increase the risk of blood clots.

Pregnancy Monitoring

During pregnancy, hematocrit levels are closely monitored to ensure the health of both mother and baby. Pregnancy-related anemia is common and may require treatment to support fetal development.

How often should hematocrit levels be checked? For healthy individuals, hematocrit is typically measured as part of routine health check-ups. Those with chronic conditions or ongoing treatments may require more frequent monitoring, as determined by their healthcare provider.

Improving Hematocrit Levels: Strategies for Optimal Blood Health

If you’ve been diagnosed with abnormal hematocrit levels, there are several strategies you can employ to improve your blood health:

Dietary Modifications

Incorporating iron-rich foods into your diet can help boost hematocrit levels. Some excellent sources include:

• Lean red meat
• Poultry
• Fish
• Beans and lentils
• Dark leafy greens
• Fortified cereals

Pairing these foods with vitamin C-rich items can enhance iron absorption.

Supplementation

In some cases, your healthcare provider may recommend supplements to address specific deficiencies. These may include iron, vitamin B12, or folate supplements. Always consult with a healthcare professional before starting any supplementation regimen.

Lifestyle Changes

Certain lifestyle modifications can support healthy hematocrit levels:

• Stay hydrated: Proper hydration helps maintain appropriate blood volume
• Exercise regularly: Physical activity can stimulate red blood cell production
• Quit smoking: Smoking can interfere with red blood cell production and function
• Manage stress: Chronic stress can impact overall health, including blood cell production

Medical Treatments

Depending on the underlying cause of abnormal hematocrit levels, medical treatments may be necessary. These can include:

• Iron injections or infusions for severe iron-deficiency anemia
• Erythropoiesis-stimulating agents to boost red blood cell production
• Blood transfusions in cases of severe anemia
• Treatment of underlying conditions contributing to abnormal hematocrit levels

How long does it take to see improvements in hematocrit levels? The timeline for improvement can vary depending on the cause and chosen treatment. Some individuals may see changes within a few weeks, while others may require several months of consistent treatment and monitoring.

Hematocrit in Special Populations: Considerations and Implications

Hematocrit levels and their interpretation can vary in certain populations. Understanding these differences is crucial for accurate diagnosis and treatment:

Athletes

Endurance athletes often have higher than average hematocrit levels due to the body’s adaptation to increased oxygen demands. This phenomenon, known as “sports anemia,” is generally considered a normal physiological response to intense training.

Elderly Individuals

Older adults may naturally have slightly lower hematocrit levels due to decreased bone marrow function and chronic health conditions. However, significant drops should still be investigated to rule out underlying issues.

Infants and Children

Hematocrit levels in infants and children can vary widely as they grow and develop. Regular monitoring during well-child visits helps ensure proper development and can catch potential issues early.

Pregnant Women

During pregnancy, blood volume increases more rapidly than red blood cell production, leading to a natural decrease in hematocrit levels. This “physiological anemia of pregnancy” is normal, but severe drops may require intervention.

Individuals with Chronic Diseases

People with chronic conditions such as kidney disease, cancer, or autoimmune disorders may have consistently abnormal hematocrit levels. In these cases, regular monitoring and specialized treatment plans are essential.

How do healthcare providers account for these population-specific differences? They consider factors such as age, sex, pregnancy status, and underlying health conditions when interpreting hematocrit results and developing treatment plans.

The Future of Hematocrit Testing: Advancements and Innovations

As medical technology continues to advance, the field of hematology is experiencing exciting developments that could impact hematocrit testing and interpretation:

Point-of-Care Testing

Portable devices that can provide rapid hematocrit results are becoming more common. These tools allow for immediate testing in various settings, from emergency rooms to remote clinics, enabling faster diagnosis and treatment decisions.

Artificial Intelligence in Analysis

AI algorithms are being developed to analyze blood test results, including hematocrit, alongside other health data. This could lead to more accurate predictions of health risks and personalized treatment recommendations.

Gene Therapy for Blood Disorders

Ongoing research into gene therapy for conditions like sickle cell disease and thalassemia could revolutionize treatment for disorders that affect hematocrit levels.

Microfluidic Devices

These miniaturized labs-on-a-chip have the potential to perform complex blood analyses, including hematocrit measurements, using tiny amounts of blood.

Wearable Technology

While still in early stages, researchers are exploring the possibility of wearable devices that can continuously monitor various blood parameters, including hematocrit-related measures.

How might these advancements change the landscape of hematocrit testing? As technology progresses, we may see more frequent, less invasive, and more comprehensive blood health monitoring, allowing for earlier detection of issues and more personalized healthcare approaches.

In conclusion, hematocrit is a fundamental measure of blood health that provides valuable insights into various aspects of an individual’s well-being. From its role in diagnosing anemia to its importance in monitoring chronic conditions, understanding hematocrit and its implications is crucial for both healthcare providers and patients. As we continue to advance our knowledge and technology in this field, the future holds promising developments that may further enhance our ability to maintain optimal blood health and overall wellness.

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.

Read this article in Spanish.

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.