Purpose, What It Measures, and Normal Results

Written by WebMD Editorial Contributors

• What Is a Complete Blood Count?
• How Is a CBC Done?
• What Does a CBC Measure?
• CBC Results
• What Else Might My CBC Tell Me?

A complete blood count (CBC) is a test that counts the cells that make up your blood: red blood cells, white blood cells, and platelets. Your doctor may order a CBC as part of a routine checkup or to:

• Check for anemia, a condition that causes you to have fewer red blood cells than usual
• Find out if you have another health issue or to explain symptoms like weakness, fever, bruising, or feeling tired
• Keep an eye on a blood condition
• See how medications, medical conditions, or treatments like chemotherapy are affecting your blood

If the CBC is the only blood test you’re having, you can eat and drink like you usually would.

Your part of the test is simple and takes just a few minutes. A nurse or lab tech will take a sample of blood by putting a needle into a vein in your arm. Afterward, you can leave and get back to your routine. They’ll send the blood to a lab for review.

The test can tell your doctor a lot about your overall health. It measures:

• White blood cells (WBCs). These help your body fight germs. If you have too many of them, it could be a sign of inflammation, infection, a medical reaction, or another health condition. If it’s low, you could be at a higher risk for infection. A medication, a viral infection, or a bone marrow disease could also cause a low count.
• Red blood cells (RBC). These deliver oxygen throughout your body. They also help carry carbon dioxide. If your RBC count is too low, you may have anemia or another condition.
• Hemoglobin (Hb or Hgb). This is the protein in your blood that holds oxygen.
• Hematocrit (Hct). This test tells how much of your blood is made up of red blood cells. A low score may be a sign that you don’t have enough iron, the mineral that helps your body make red blood cells. A high score could mean you’re dehydrated or have another condition.
• Mean corpuscular volume (MCV). This is the average size of your red blood cells. If they’re bigger than usual, your MCV will be higher. That could happen if you have low vitamin B12 or folate levels. If your red blood cells are smaller, you could have a type of anemia.
• Platelets. These help your blood clot.

When you get your report, you’ll see two columns: a “reference range” and your results. If your results are inside the reference range, they’re considered normal. If your results are higher or lower than the reference range, they’re abnormal. Mild anemia is one of the most common reasons your results might be off.

Each lab has different ways of studying your blood. So the reference range will depend on the lab that handles your blood tests. It’s also based on things that can affect your blood like your age, your sex, and how high above sea level you live.

In general, the reference ranges are:

• White blood cells: 4,500 to 11,000 cells per microliter (cells/mcL)
• Red blood cells: 4.5 million to 5.9 million cells/mcL for men; 4.1 million to 5.1 million cells/mcL for women
• Hemoglobin: 14 to 17.5 grams per deciliter (gm/dL) for men; 12.3 to 15.3 gm/dL for women
• Hematocrit: 41.5% to 50.4% for men; 35.9% to 44.6% for women
• Mean corpuscular volume: 80 to 96
• Platelets: 150,000 to 450,000 platelets/mcL

Your doctor might order more results to learn whether you have an illness or blood condition, including:

• Mean corpuscular hemoglobin (MCH). This test tells how much hemoglobin is in your typical red blood cell.
• Mean corpuscular hemoglobin concentration (MCHC).  This measures the concentration of hemoglobin in a certain amount of blood.
• Red cell distribution width (RDW). This shows how much your red blood cells vary in size.
• Reticulocyte count. This test measures the number of new red blood cells in your body.
• Mean platelet volume (MPV). This result gives the average size of the platelets in your blood.
• Platelet distribution width (PDW). This shows how much your platelets vary in size.
• White blood cell differential. There are five types of white blood cells: basophils, eosinophils, lymphocytes, monocytes, and neutrophils. This test shows how many of each kind you have.

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Purpose, What It Measures, and Normal Results

Written by WebMD Editorial Contributors

• What Is a Complete Blood Count?
• How Is a CBC Done?
• What Does a CBC Measure?
• CBC Results
• What Else Might My CBC Tell Me?

A complete blood count (CBC) is a test that counts the cells that make up your blood: red blood cells, white blood cells, and platelets. Your doctor may order a CBC as part of a routine checkup or to:

• Check for anemia, a condition that causes you to have fewer red blood cells than usual
• Find out if you have another health issue or to explain symptoms like weakness, fever, bruising, or feeling tired
• Keep an eye on a blood condition
• See how medications, medical conditions, or treatments like chemotherapy are affecting your blood

If the CBC is the only blood test you’re having, you can eat and drink like you usually would.

Your part of the test is simple and takes just a few minutes. A nurse or lab tech will take a sample of blood by putting a needle into a vein in your arm. Afterward, you can leave and get back to your routine. They’ll send the blood to a lab for review.

The test can tell your doctor a lot about your overall health. It measures:

• White blood cells (WBCs). These help your body fight germs. If you have too many of them, it could be a sign of inflammation, infection, a medical reaction, or another health condition. If it’s low, you could be at a higher risk for infection. A medication, a viral infection, or a bone marrow disease could also cause a low count.
• Red blood cells (RBC). These deliver oxygen throughout your body. They also help carry carbon dioxide. If your RBC count is too low, you may have anemia or another condition.
• Hemoglobin (Hb or Hgb). This is the protein in your blood that holds oxygen.
• Hematocrit (Hct). This test tells how much of your blood is made up of red blood cells. A low score may be a sign that you don’t have enough iron, the mineral that helps your body make red blood cells. A high score could mean you’re dehydrated or have another condition.
• Mean corpuscular volume (MCV). This is the average size of your red blood cells. If they’re bigger than usual, your MCV will be higher. That could happen if you have low vitamin B12 or folate levels. If your red blood cells are smaller, you could have a type of anemia.
• Platelets. These help your blood clot.

When you get your report, you’ll see two columns: a “reference range” and your results. If your results are inside the reference range, they’re considered normal. If your results are higher or lower than the reference range, they’re abnormal. Mild anemia is one of the most common reasons your results might be off.

Each lab has different ways of studying your blood. So the reference range will depend on the lab that handles your blood tests. It’s also based on things that can affect your blood like your age, your sex, and how high above sea level you live.

In general, the reference ranges are:

• White blood cells: 4,500 to 11,000 cells per microliter (cells/mcL)
• Red blood cells: 4.5 million to 5.9 million cells/mcL for men; 4.1 million to 5.1 million cells/mcL for women
• Hemoglobin: 14 to 17.5 grams per deciliter (gm/dL) for men; 12. 3 to 15.3 gm/dL for women
• Hematocrit: 41.5% to 50.4% for men; 35.9% to 44.6% for women
• Mean corpuscular volume: 80 to 96
• Platelets: 150,000 to 450,000 platelets/mcL

Your doctor might order more results to learn whether you have an illness or blood condition, including:

• Mean corpuscular hemoglobin (MCH). This test tells how much hemoglobin is in your typical red blood cell.
• Mean corpuscular hemoglobin concentration (MCHC). This measures the concentration of hemoglobin in a certain amount of blood.
• Red cell distribution width (RDW). This shows how much your red blood cells vary in size.
• Reticulocyte count. This test measures the number of new red blood cells in your body.
• Mean platelet volume (MPV). This result gives the average size of the platelets in your blood.
• Platelet distribution width (PDW).  This shows how much your platelets vary in size.
• White blood cell differential. There are five types of white blood cells: basophils, eosinophils, lymphocytes, monocytes, and neutrophils. This test shows how many of each kind you have.

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Erythrocytes (red blood cells, red blood cells, RBC)

Large population of blood cells containing hemoglobin. The erythrocyte has the shape of a biconcave disk, which increases its surface area and provides the largest gas exchange surface.

Functions of erythrocytes:

• participation in gas exchange;
• maintenance of the acid-base state, since hemoglobin is the main buffer system of the body;
• influence on the rheological properties of blood: erythrocytes make up to 45% of the blood volume, their state is changed by hematocrit and blood viscosity;
• participation in immune processes by interaction with antibodies, circulating immune complexes.

The number of red blood cells (RBC) is one of the most important indicators of the blood system. A decrease in the number of red blood cells in the blood is one of the diagnostic criteria for anemia.

Reference values ​​(standard version)

Red blood cells (RBC) – 10 ¹² cells/l

Age	Men	Women
< 2 weeks	3.9 – 5.9	3.9 – 5.9
2 weeks – 1 month	3. 3 – 5.3	3.3 – 5.3
1 month – 4 months	3.5 – 5.1	3.5 – 5.1
4 months – 6 months	3.9 – 5.5	3.9 – 5.5
6 months – 9 months	4.0 – 5.3	4.0 – 5.3
9 months – 1 year	4.1 – 5.3	4.1 – 5.3
1 year – 3 years	3.8 – 4.8	3.8 – 4.8
3 years – 6 years	3.7 – 4.9	3.7 – 4.9
6 – 9 years old	3.8 – 4.9	3.8 – 4.9
9 – 12 years old	3.9 – 5.1	3.9 – 5.1
12 – 15 years old	4.1 – 5.2	3.8 – 5.0
15 – 18 years old	4.2 – 5.6	3.9 – 5.1
18 – 45 years old	4. 3 – 5.7	3.8 – 5.1
45 – 65 years old	4.2 – 5.6	3.8 – 5.3
> 65 years old	3.8 – 5.8	3.8 – 5.2

causes of increased and decreased values ​​

Contents

• 1 Erythrocytes in the blood: norm, causes of increase and decrease
  • 1. 1 Concept and meaning
    • 1.1.1 What is the norm of erythrocytes in the blood
    • 1.1.2 Why is it important the norm of erythrocytes in the blood
  • 1.2 The norms of the level of erythrocytes in the blood in adults and children
    • 1.2.1 The norms of erythrocytes in the blood in adults
    • 1.2.2 Red blood cell counts in children
  • 1.3 Causes of low red blood cell counts
  • 1.4 Anemia
  • 1.5 Genetic disorders affecting the red blood cell count
  • 1. 6 Chronic diseases and their impact on the level of red blood cells
  • 1.7 Elevated red blood cells: causes
  • 1.8 Polycythemia: causes, symptoms and treatment
  • 1.9 Other blood disorders
    • 1.9.1 Anemia
    • 1.9.2 Leukemia
    • 1.9.3 Thrombocytopenia
  • 1.10.2 Wrong power supply
  • 1.10.3 Output
• 1.11 Prevention and treatment of abnormal red blood cells
  • 1. 11.1 Low red blood cells:
  • 1.11.2 High red blood cells:
• 1.12 Related videos:
• 1.13 Q&A:
  • • 1.13.0.1 What causes an increase in the level of erythrocytes in the blood?
    • 1.13.0.2 What symptoms may indicate a low level of red blood cells?
    • 1.13.0.3 What is the normal level of red blood cells in women?
    • 1.13.0.4 How does the level of red blood cells in the blood during pregnancy?
    • 1.13.0.5 What measures can be taken to correct the level of erythrocytes in the blood?
    • 1.13.0.6 What are the indications for testing the level of erythrocytes in the blood?

Learn about normal red blood cell counts and what causes high and low levels. All about the physiology and diseases associated with the number of red cells in the blood.

Red blood cells are red blood cells that are responsible for transporting oxygen throughout the body. The normal level of red blood cells in the blood is one of the key indicators of human health. This parameter depends on many factors, such as nutrition, physical activity, environmental conditions.

If the level of red blood cells is higher than normal, it is possible that there is a violation in the formation of red blood cells in the body or there is some kind of disease. In this article, we will look at the causes of high and low RBC values ​​and explain in detail how this characteristic affects health.

It is important to understand that all changes in the level of red blood cells require the attention of doctors and a preventive approach. Some diseases can become extremely serious if they are not addressed in a timely manner.

Concept and meaning

What is the red blood cell count

The red blood cell count is the acceptable range of red blood cells in the blood in a certain period of time. It is usually measured in terms of the number of red blood cells per microliter of blood. The normal level may vary in men, women and children depending on age, gender and health status.

Why is the rate of red blood cells important

The rate of red blood cells is important for maintaining the normal functioning of the body. Red blood cells carry oxygen to the tissues and also help remove carbon dioxide from the lungs. If the level of red blood cells is lower or higher than normal, this may indicate the presence of diseases or health problems. Therefore, regular monitoring of the level of red blood cells is an important element in the prevention of diseases and maintaining the health of the body as a whole.

Red blood cell norms in adults and children

Red blood cell norms in adults

The level of red blood cells in the blood of an adult is from 3.8 to 5.8 million/µl in men and from 3.8 to 5.0 million/µl in women.

In healthy adults, the level of red blood cells in the blood does not change throughout life, except for temporal variability associated with the physiological processes of the body.

Norms of erythrocytes in the blood of children

• In newborns, the level of erythrocytes reaches a maximum value and ranges from 4. 2 to 7.4 million / μl.
• In infants, the normal level of red blood cells in the blood is from 3.9 to 5.5 million/µl.
• At the age of 1 to 14 years, the norm of the level of red blood cells in the blood of children is significantly reduced and ranges from 3.5 to 4.8 million/µl.
• Adolescents under 18 years of age have a higher red blood cell count than adults, approximately 4.0 to 5.5 million/mcL.

It is important to note that RBC levels may vary slightly in children based on race and gender.

Causes of low red blood cells

Anemia is the most common cause of low red blood cells. Anemia can be caused by a lack of iron, vitamin B12, or folic acid, as well as other factors such as blood loss, bone marrow disease, and hereditary factors.

Chronic diseases such as chronic infections, cancer and kidney disease can lead to a decrease in the number of red blood cells.

Acute blood loss caused, for example, by trauma, surgery or childbirth, can lead to a decrease in the number of red blood cells.

The body perceives its own erythrocytes as foreign. This can occur in autoimmune diseases, in which the immune system attacks its own cells, including red blood cells.

heredity can also be a cause of low red blood cells, as genetic mutations can lead to disruption of their formation or viability.

Anemia

Anemia is a condition in which the number of red blood cells in the blood and/or their content in hemoglobin is below normal. Anemia can develop for various reasons and have various symptoms.

Symptoms of anemia may include fatigue, weakness, pale skin, shortness of breath, dizziness, poor concentration, and others. Treatment for anemia depends on the cause and may include iron, vitamins, and other medications.

1. 1. Some types of anemia:
      • Iron deficiency anemia – associated with iron deficiency;
      • Folate deficiency anemia – due to lack of folic acid;
      • Vitamin deficiency anemia – occurs when there is a lack of vitamins necessary for the production of red blood cells.

Proper nutrition and regular examinations will help prevent anemia.

Genetic disorders affecting the rate of red blood cells in the blood

The rate of red blood cells in the blood depends on many factors, including hereditary predisposition to genetic diseases. Some of these disorders can lead to an increase in the level of red blood cells (erythrocytosis), while others can cause them to decrease (erythropenia).

Among the genetic disorders that affect the rate of red blood cells, we can distinguish:

1. 1. • Wilson-Microbe syndrome, in which erythrocytosis and an increase in the size of red cells are caused by defects in the genes that regulate the work of red blood cells;
      • Porphyria, a hereditary disease that disrupts the synthesis of hemoglobin and leads to an increase in red blood cells;
      • Spherocytosis, a hemolytic disease associated with a defect in the red blood cell membrane, leading to the destruction of red cells and a decrease in their number in the blood.

However, genetic disorders are not the only reason for changes in the rate of erythrocytes in the blood, and additional studies are required for an accurate diagnosis.

Chronic diseases and their effect on the level of red blood cells in the blood

The normal level of red blood cells in the blood depends entirely on many factors, including human health. Chronic diseases can significantly reduce or increase the level of red blood cells.

Some chronic diseases, such as heart failure, can reduce the amount of oxygen in the blood. As a result, the level of red blood cells in patients with similar diseases can increase significantly.

In general, any chronic disease can lead to changes in the level of red blood cells. Therefore, it is very important to monitor your health and lead a healthy lifestyle, which will help reduce the risk of developing not only anemia, but also other chronic diseases.

Elevated red blood cells: causes

Elevated red blood cells is called erythrocytosis, it can occur due to several reasons:

1. 1. • Hypoxia. When the supply of oxygen to the body is disturbed in the bone marrow, an increase in the production of red blood cells occurs in an attempt to compensate for the distortion of gas exchange;
      • Long stay at high altitude. Under such conditions, the level of oxygen is significantly lower than at sea level, and red blood cells begin to increase in the blood;
      • Renal diseases. When kidney function is reduced, they cannot remove excess red blood cells from the blood and their number increases;
      • Leukemia, pneumonia, acute infections, and other conditions that increase blood production in the bone marrow.

It should be noted that erythrocytosis itself is not a disease, but only a symptom. It is not always accompanied by characteristic symptoms and is not dangerous at moderate loads.

Causes of increased values ​​of red blood cells in the blood Cause Description

Hypoxia	Impaired oxygen supply to the body
Prolonged exposure to high altitude	Oxygen levels significantly lower than at sea level
Kidney disease	Decreased kidney function, inability to remove excess red blood cells
Leukemias, pneumonia , acute infections	Lead to increased blood production in the bone marrow.

Polycythemia: causes, symptoms and treatment

Polycythemia is a disease in which the number of red blood cells is increased. As a result, blood viscosity increases, which can lead to serious complications.

An increase in the number of red blood cells can be caused by various reasons. One of the most common is hypoxia – insufficient amount of oxygen in the body. Polycythemia can also occur with genetic disorders, the abuse of certain drugs, and as a result of prolonged exposure to high altitudes.

The main symptoms of polycythemia are headache, fatigue, excessive sweating, visual and hearing impairments. In more severe cases, signs of angina pectoris and cardiac arrhythmias may appear.

For the diagnosis of polycythemia, it is necessary to bring a blood test, which will determine the concentration of red blood cells and other indicators. Treatment includes reducing blood viscosity with medication and regular blood transfusions (phlebotomy). It is also necessary to avoid factors that lead to an increase in the level of red blood cells.

Other blood disorders

Anemia

Anemia is a blood disorder characterized by insufficient hemoglobin content in red blood cells. This can lead to a low level of red blood cells in the blood.

Causes of anemia include deficiency of iron, vitamin B12, or folate, red cell hemolysis, and other abnormalities in the production of red cells in the bone marrow.

Leukemia

Leukemia is a blood cancer that can cause an increase or decrease in red blood cells.

Leukemia is caused by abnormal white blood cells that interfere with the production of normal red blood cells in the bone marrow.

Thrombocytopenia

Thrombocytopenia is a blood disorder in which the level of platelets responsible for blood clotting is low. This can lead to problems with blood clots and heavy bleeding.

Decreased platelet count may result from various diseases such as leukemia, Itsenko-Cushing’s syndrome, systemic lupus erythematosus, alcohol-related liver cirrhosis, and others.

Effect of obesity and malnutrition on the rate of erythrocytes in the blood

Obesity

Obesity, which is characterized by an excess of adipose tissue in the body, can cause an increase in the number of erythrocytes in the blood. This is due to metabolic disorders and lack of oxygen in the tissues.

In addition, obesity can cause an increase in hemoglobin when the concentration of hemoglobin in red blood cells is higher than normal. This is possible due to an increase in the number of red blood cells in the blood and an increase in blood volume.

Improper nutrition

Improper nutrition, especially when accompanied by an excess of fats and carbohydrates, can lead to metabolic disorders and a decrease in the oxygen transport function of the blood.

Eating a large amount of fatty foods can lead to a decrease in the level of iron in the body and the development of iron deficiency anemia, in which the number of red blood cells in the blood decreases. Also, a frequent diet that includes a small amount of iron can lead to a similar effect on the red blood cell count.

Conclusion

Obesity and malnutrition, like other factors, can affect the rate of red blood cells in the blood. To increase the number of red blood cells in the blood, which corresponds to the norm, you need to monitor your diet, consume the necessary amount of iron and exercise to improve metabolism and maintain the oxygen transport function of the blood.

Prevention and treatment of abnormal red blood cells

Low red blood cells:

Proper nutrition is one of the key preventive measures. It is necessary to eat food containing iron (meat, fish, berries, vegetables), vitamins (especially groups B, C, E), trace elements (zinc, magnesium, cobalt). It is also recommended to exclude fatty and fried foods from the diet, drink alcohol and smoke.

In the treatment of reduced erythrocyte values, preparations containing iron are prescribed (Ferro-foilgamma, Fenulet, Maltofer). It is also recommended to conduct a course of vitamin therapy, increase physical activity and it is necessary to adjust the diet.

Elevated erythrocyte values:

Prevention of elevated values ​​comes down to a proper lifestyle: daily routine, sufficient physical activity, proper nutrition. It is necessary to exclude fatty, fried, sweet and smoked foods, alcohol from the diet.

The treatment of elevated erythrocyte values ​​during the diagnosis and identification of the causes of deviations is prescribed by a doctor. Usually, blood circulation is carried out, treatment of other diseases (for example, hypertension, diabetes), drugs that thin the blood (aspirin, phlebodia) are prescribed.

Related videos:

Q&A:

What causes an increase in the level of erythrocytes in the blood?

Elevated red blood cells may be due to various causes such as dehydration, hypoxia, lung disease, heart failure, certain medications or smoking.

What symptoms can indicate a low level of red blood cells?

A low red blood cell count may present with the following symptoms: pale skin, tiredness, weakness, shortness of breath, palpitations, dizziness.

What is the normal level of red blood cells in women?

The normal level of red blood cells in women is 3.5 to 5 million/mcL.

How does the level of red blood cells in the blood during pregnancy?

The red blood cell level in women during pregnancy is usually low, and there may be changes in other blood parameters associated with pregnancy, such as hemoglobin levels and color index.

What measures can be taken to correct the level of erythrocytes in the blood?

To correct the level of erythrocytes in the blood, it is necessary to identify the cause of the deviation and take measures to eliminate this cause. For example, in case of dehydration, it is necessary to increase the amount of fluid consumed, in case of pulmonary diseases, take appropriate therapy.