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Complete blood count components: CBC blood test Information | Mount Sinai

CBC blood test Information | Mount Sinai

Complete blood count; Anemia – CBC

A complete blood count (CBC) test measures the following:

  • The number of white blood cells (WBC count)
  • The number of red blood cells (RBC count)
  • The number of platelets
  • The total amount of hemoglobin in the blood
  • The fraction of the blood composed of red blood cells (hematocrit)

The CBC test also provides information about the following measurements:

  • Mean red blood cell volume (MCV)
  • Mean hemoglobin amount per red blood cell (MCH)
  • The mean amount of hemoglobin relative to the size of the cell (hemoglobin concentration) per red blood cell (MCHC)

The complete blood count (CBC) is test, used to diagnose and monitor numerous diseases. It can reflect problems with fluid volume (such as dehydration) or loss of blood. It can show abnormalities in the production, life span, and destruction of blood cells. It can reflect acute or chronic infection, allergies, and problems with clotting. The CBC test identifies and counts the 7 types of cells found in the blood, red blood cell, neutrophil, eosinophil, basophil, lymphocyte, monocyte, and platelet.

Sickle cell anemia is an inherited blood disease in which the red blood cells produce abnormal pigment (hemoglobin). The abnormal hemoglobin causes deformity of the red blood cells into crescent or sickle-shapes, as seen in this photomicrograph.

This picture shows large, dense, oversized, red blood cells (RBCs) that are seen in megaloblastic anemia. Megaloblastic anemia can occur when there is a deficiency of vitamin B-12.

This photomicrograph shows one of the abnormal shapes that red blood cells (RBCs) may assume, a tear-drop shape. Normally, RBCs are round.

This photomicrograph shows normal red blood cells (RBCs) as seen in the microscope after staining.

Elliptocytosis is a hereditary disorder of the red blood cells (RBCs). In this condition, the RBCs assume an elliptical shape, rather than the typical round shape.

Spherocytosis is a hereditary disorder of the red blood cells (RBCs), which may be associated with a mild anemia. Typically, the affected RBCs are small, spherically shaped, and lack the light centers seen in normal, round RBCs.

Sickle cell anemia is an inherited disorder in which abnormal hemoglobin (the red pigment inside red blood cells) is produced. The abnormal hemoglobin causes red blood cells to assume a sickle shape, like the ones seen in this photomicrograph.

Basophils are a specific type of white blood cell. These cells are readily stained with basic dyes (this is where the name comes from). Note the dark grains inside the cellular fluid (cytoplasm) of this basophil. Basophils make up only a small portion of the number of white blood cells but are important parts of the body’s immune response. They release histamine and other chemicals that act on the blood vessels when the immune response is triggered.

Malarial parasites are visible within the red blood cells. They are stained a dark bluish color.

Malaria is a disease caused by parasites. This picture shows dark orange-stained malaria parasites inside red blood cells (a) and outside the cells (b). Note the large cells that look like targets; it is unknown how these target cells are related to this disease.

These crescent or sickle-shaped red blood cells (RBCs) are present with Sickle cell anemia, and stand out clearly against the normal round RBCs. These abnormally shaped cells may become entangled and block blood flow in the small blood vessels (capillaries).

This photomicrograph of red blood cells (RBCs) shows both sickle-shaped and Pappenheimer bodies.

These abnormal red blood cells (RBCs) resemble targets. These cells are seen in association with some forms of anemia, and following the removal of the spleen (splenectomy).

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

There is no special preparation needed.

How the Test will Feel

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

Why the Test is Performed

A CBC is a commonly performed lab test. It can be used to detect or monitor many different health conditions. Your health care provider may order this test:

  • If you are having symptoms, such as fatigue, weight loss, fever or other signs of an infection, weakness, bruising, bleeding, or any signs of cancer
  • When you are receiving treatments (medicines or radiation) that may change your blood count results
  • To monitor a long-term (chronic) health problem that may change your blood count results, such as chronic kidney disease

Normal Results

Blood counts may vary with altitude. In general, normal results are:

RBC count:

  • Male: 4.7 to 6.1 million cells/mcL
  • Female: 4.2 to 5.4 million cells/mcL

WBC count:

  • 4,500 to 10,000 cells/mcL


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


  • Male: 13.8 to 17.2 gm/dL
  • Female: 12.1 to 15.1 gm/dL

Red blood cell indices:

  • MCV: 80 to 95 femtoliter
  • MCH: 27 to 31 pg/cell
  • MCHC: 32 to 36 gm/dL

Platelet count:

  • 150,000 to 450,000/dL

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

What Abnormal Results Mean

High RBC, hemoglobin, or hematocrit may be due to:

  • A lack of enough water and fluids, such as from severe diarrhea, excessive sweating, or water pills used to treat high blood pressure
  • Kidney disease with high erythropoietin production
  • Low oxygen level in the blood for a long time, most often due to heart or lung disease, chronic carbon monoxide exposure, or living at a high altitude
  • Polycythemia vera
  • Smoking
  • Use of testosterone

Low RBC, hemoglobin, or hematocrit is a sign of anemia, which can result from:

  • Blood loss (either sudden, or from problems such as heavy menstrual periods over a long time)
  • Bone marrow failure (for example, from radiation, infection, or tumor)
  • Breakdown of red blood cells (hemolysis)
  • Cancer and cancer treatment
  • Certain long-term (chronic) medical conditions, such as chronic kidney disease, ulcerative colitis, or rheumatoid arthritis
  • Iron deficiency
  • Leukemia
  • Long-term infections such as hepatitis
  • Poor diet and nutrition, causing too little iron, folate, vitamin B12, or vitamin B6
  • Multiple myeloma

A lower than normal white blood cell count is called leukopenia. A decreased WBC count may be due to:

  • Alcohol abuse and liver damage
  • Autoimmune diseases (such as systemic lupus erythematosus)
  • Bone marrow failure (for example, due to infection, tumor, radiation, or fibrosis)
  • Chemotherapy medicines used to treat cancer
  • Disease of the liver or spleen
  • Enlarged spleen
  • Infections caused by viruses, such as mono or AIDS
  • Medicines

A high WBC count is called leukocytosis. It can result from:

  • Certain medicines, such as corticosteroids
  • Infections
  • Diseases such as lupus, rheumatoid arthritis, or allergy
  • Leukemia
  • Severe emotional or physical stress
  • Tissue damage (such as from burns or a heart attack)

A high platelet count may be due to:

  • Bleeding
  • Diseases such as cancer or blood disease
  • Iron deficiency
  • Problems with the bone marrow

A low platelet count may be due to:

  • Disorders where platelets are destroyed
  • Pregnancy
  • Enlarged spleen
  • Bone marrow failure (for example, due to infection, tumor, radiation, or fibrosis)
  • Chemotherapy medicines used to treat cancer


There is very 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. Taking blood 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
  • Hematoma (blood accumulating under the skin)
  • Infection (a slight risk any time the skin is broken)


RBCs transport hemoglobin which, in turn, carries oxygen. The amount of oxygen received by body tissues depends on the amount and function of RBCs and hemoglobin.

WBCs are mediators of inflammation and the immune response. There are various types of WBCs that normally appear in the blood:

  • Neutrophils (polymorphonuclear leukocytes)
  • Band cells (slightly immature neutrophils)
  • T-type lymphocytes (T cells)
  • B-type lymphocytes (B cells)
  • Monocytes
  • Eosinophils
  • Basophils

Lin JC, Benz Jr. EJ. Approach to anemia in the adult and child. In: Hoffman R, Benz EJ, Silberstein LE, et al, eds. Hematology: Basic Principles and Practice. 8th ed. Philadelphia, PA: Elsevier; 2023:chap 35.

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: 10/16/2022

Reviewed by: Mark Levin, MD, Hematologist and Oncologist, Monsey, NY. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

CBC Blood Test (Complete Blood Count)

Test Quick Guide

The complete blood count (CBC) is an essential comprehensive blood panel that allows your doctor to evaluate each type of cell in your blood.

The CBC measures the number of red blood cells (RBC), white blood cells (WBC), and platelets (PLT). Each of these types of blood cells performs important functions, so determining their levels can provide important health information.

A CBC may be used to help diagnose a range of health conditions and also monitor how the body is affected by different diseases or medical treatments.

About the Test

Purpose of the test

The purpose of a CBC is to give your health care provider details about the state of your health. It is an important medical tool because it uses one sample to analyze the complete spectrum of cells found in the blood as well as some of the characteristics of those cells.

Because it provides information about every type of cell in the blood, the CBC can provide information related to a wide variety of medical problems.

The primary uses for the CBC are diagnosis, monitoring, and screening:

  • Diagnosis is determining the cause of a patient’s symptoms. The CBC can identify many different abnormalities in the blood that can be linked to distinct medical problems. For this reason, the CBC is frequently used as a diagnostic test. In many cases, it can confirm or rule out certain conditions and may be used alongside other tests to arrive at a definitive diagnosis.
  • Monitoring is the process of following a patient’s condition over time. A CBC can be used to monitor patients who have previously been diagnosed with blood cell disorders. It can help see how a person’s condition has responded to treatment and may be used to watch for side effects of some medical treatments.
  • Screening is testing to find health problems before there are any symptoms. In some cases, a doctor may prescribe a CBC as a screening test during routine check-ups.

What does the test measure?

A CBC involves multiple measurements that include the number of blood cells and some of their physical features. A standard CBC includes several elements related to RBCs, WBCs, and PLT that are described in the following sections.

Red blood cell measurements

RBC, also called erythrocytes, carry oxygen from your lungs to the tissues and organs in your body. A CBC test includes several basic measurements of RBCs:

  • RBC count is the total number of RBCs in your blood sample.
  • Hemoglobin measures the amount of this oxygen-carrying protein that is found inside RBCs.
  • Hematocrit measures the proportion of your total blood volume that consists of RBCs.

A CBC also provides details about the physical features of RBC. These are known as RBC indices, of which there are several kinds:

  • Mean corpuscular volume (MCV) is a measurement of the average size of RBC.
  • Mean corpuscular hemoglobin (MCH) is the average amount of hemoglobin inside each RBC.
  • Mean corpuscular hemoglobin concentration (MCHC) is a calculated measurement of how concentrated hemoglobin is within RBC.
  • Red cell distribution width (RDW) is a measurement of the variation in the size of your RBC.

The CBC may include the reticulocyte count, the total number of newly released young RBCs in your blood sample. It may also be measured as a percentage.

White blood cell measurements

WBCs, also called leukocytes, are an important part of the body’s immune system.

A standard CBC includes measures of the WBC count, which is the total number of WBCs in a sample of blood.

A common variation of the CBC is the CBC with differential. The WBC differential is a breakdown of the amount of each of five different types of WBCs:

  • Neutrophils: Neutrophils make up the greatest percentage of WBCs and are produced by the bone marrow to fight a diverse array of inflammatory and infectious diseases.
  • Lymphocytes: Lymphocytes such as B-cells and T-cells are found primarily in the lymph system and fight bacteria and other pathogens in the blood.
  • Monocytes: Monocytes work in conjunction with neutrophils to combat infections and other illnesses while removing damaged or dead cells.
  • Eosinophils: Eosinophils are WBCs activated in response to allergies and some types of infections.
  • Basophils: Basophils are involved in the early identification of infections as well as wound repair and allergic reactions.

Initial blood testing may include a CBC with differential, or this test may be done after an abnormal initial standard CBC. Because each WBC type has a different function, the CBC with differential can be used to identify abnormal levels of specific WBCs, which may offer clues about an underlying health concern.

Platelet measurements

Platelets (PLT), also called thrombocytes, are cell fragments that circulate in the blood and play an essential role in blood clotting. When there is an injury and bleeding begins, PLT help stop bleeding by sticking to the injury site and clumping together to form a temporary plug.

A standard component of the CBC is the PLT count, which is the number of PLT in your blood sample.

In some cases, your doctor may have the laboratory also measure the mean PLT volume (MPV), which determines the average size of PLT.

When should I get a complete blood count?

The CBC is a very common test. You may have a CBC performed when you have a routine health examination, are being diagnosed or assessed for a disease or condition, or when your provider is monitoring the effectiveness of a treatment.

Because blood counts can be affected by a diverse range of health conditions, the CBC may be recommended by your doctor to help identify the cause of many different kinds of symptoms. Your health care provider is in the best position to address whether a CBC is appropriate in your specific situation.

Finding a Complete Blood Count Test

How can I get a complete blood count test?

A CBC requires a needle blood draw and is most commonly conducted by a licensed professional in a health care setting like a hospital or doctor’s office.

Can I take the test at home?

There are few options available for at-home CBC testing. Kits for use at home involve a fingerstick; you prick your finger with a small needle to produce a drop of blood. That blood is applied to a special test paper and is then sent to a lab.

After the lab is done analyzing the blood, it provides results either online or through a smartphone app. Results usually take two to three days after the sample is received.

These at-home tests do not provide a diagnosis or confirm a specific illness or disease. Diagnosis and disease confirmation can only be provided by a doctor. For this reason, it is important to talk to a doctor before and after taking an at-home blood count test.

How much does the test cost?

The cost of a CBC test depends on several factors, including whether or not the patient is paying out of pocket or has health insurance. Because the CBC is common and has many uses, the cost is often covered by insurance. However, there may still be charges for copays and deductibles.

Talk to your doctor or insurance provider for specific details about expected costs for a CBC. If you do not have insurance, a hospital or laboratory administrator may be able to provide information about typical costs for uninsured patients.

Taking a CBC

The CBC is ordered and conducted by a licensed professional. The blood sample is drawn from a vein, usually on the inside of your elbow.

Before the test

Unless specified by your provider, there is no special preparation required before a CBC.

In some instances, a CBC is done along with other blood tests. When you are getting more than one blood test, your provider may ask you to not eat anything for a certain amount of time prior to your test.

If you have questions or concerns about any test preparation, contact your health care provider for specific instructions.

During the test

There are several steps that you can expect during a needle blood draw for a CBC:

  1. An antiseptic alcohol wipe is used to cleanse your arm in the area that the needle will be inserted. This is most often either inside the elbow or at the top of the hand.
  2. To make the vein in your arm more visible and easier to access with a needle, a band called a tourniquet is tied around your upper arm.
  3. A needle is placed in your vein, and a test tube attached to the needle is filled with blood. When the needle is inserted there may be a pinch or a little pain.
  4. After the test tube or vial is filled, the needle is removed, and the test is over.

After the test

After the needle is removed, a bandage will be placed over the puncture site.

Slight bruising is a common side effect after any blood draw while dizziness or lightheadedness are less common. Your provider may have you stay for a few minutes after the blood draw to monitor you until they are sure you are safe to walk and/or drive.

If you notice any other effects or signs of bleeding or infection after your blood draw, it is important to promptly contact your health care provider.

Complete Blood Count Test Results

Receiving test results

Depending on the laboratory equipment that is used, the results from a CBC can be available in a few minutes to a few days after the blood sample arrives at the laboratory. You may receive a copy of your results by mail or through an electronic health portal. Your doctor may also call you to discuss the results or to schedule an appointment to review them together.

Interpreting test results

The results from a CBC test will include separate levels listed for each component of the test including RBC, WBC, and PLT.

For each test component, the report will also show a reference range that defines what the laboratory that performed the test considers normal. These ranges, which can vary from lab to lab, are based on the results of a large sample of healthy people and help your doctor determine typical and atypical blood levels.

It is essential to talk with your doctor about the significance of your CBC test results. Your doctor will review your levels and how they compare to the laboratory’s reference ranges. They may also look at the relationships between your different blood levels and will consider your current symptoms and health history.

The following sections describe some potential causes of high or low levels of RBCs, WBCs, or PLT, but it is important to remember that an abnormal test result is not always a sign of a medical problem. Some healthy people may have blood counts that fall outside the standard reference range.

Red blood cell measurements

RBCs carry oxygen through the body, and the RBC count shows the total number of RBCs found in your blood. Hematocrit and hemoglobin are other related measures.

Anemia is a condition marked by low levels of RBCs. There are many potential causes of abnormally low levels of RBCs, hematocrit, and/or hemoglobin, including:

  • Excessive acute or chronic bleeding
  • Destruction of RBCs, such as in a condition called hemolytic anemia
  • Disorders that affect the bone marrow, which produces new RBCs
  • Nutritional deficiencies such as low iron, folate, or vitamin B12
  • Some types of cancer and cancer treatment
  • Chronic illnesses involving inflammation or disrupted organ function

High levels of RBCs, hematocrit, and/or hemoglobin can also have a number of possible causes. Examples include:

  • Dehydration
  • Heart or lung disease that reduces oxygen levels
  • Certain kinds of kidney diseases
  • Cigarette smoking
  • Polycythemia vera, a rare disease causing overproduction of RBCs

In many cases, the CBC will include a set of measurements known as RBC indices that include the MCV, MCH, and MCHC. These indices can help distinguish between the most likely causes of anemia.

RBC counts are influenced by many different systems of the body, and sometimes abnormal levels are related to more than one factor. Your health care provider is in the best position to explain what the RBC measurements on your CBC mean for your health.

White blood cell counts

WBCs are the main players of the immune system, and the WBC count is the sum total of five different kinds of WBCs; each plays a role in immune function.

A low level of WBCs is known as leukopenia. Some of the possible causes of leukopenia include:

  • Liver damage, including from alcohol abuse
  • Severe infections
  • An enlarged or damaged spleen
  • Autoimmune diseases
  • Conditions that disrupt bone marrow function
  • Certain medications, including many chemotherapies for cancer

Having too many WBCs is known as leukocytosis. Excess WBCs may be related to several potential causes:

  • Infections
  • Tissue death from injury, burns, or other physical trauma
  • Allergies and autoimmune conditions
  • Stress
  • Some medications
  • Leukemia and some other cancers

If you have a CBC with WBC differential, your test report will show the specific levels of each kind of WBC. These are known as neutrophils, lymphocytes, monocytes, eosinophils, and basophils. Knowing the counts of each type of WBC can provide detailed information to help your doctor interpret the findings of your CBC.

Platelet count

PLT are responsible for clotting the blood. Abnormal PLT function can mean you bleed too easily because your blood doesn’t clot properly, or your blood is prone to excess clotting.

Thrombocytopenia, a low PLT count, puts you at risk of excessive bleeding or bruising. Possible causes of a low PLT count include:

  • Blood disorders that cause PLT destruction
  • Some medications, including many chemotherapies
  • An enlarged spleen
  • Damage to the bone marrow
  • Pregnancy

Having too many PLT is called thrombocytosis, and it is associated with a higher risk of cardiovascular complications from blood clots. Abnormally high PLT counts may be caused by several conditions including:

  • Iron deficiency
  • Some cancers
  • Bone marrow dysfunction
  • Recent infection or other tissue trauma

The test may also measure the MPV (the size of your PLT). The MPV level can help your doctor understand how rapidly your body is producing new PLT.

Examples of questions that you can ask your doctor to learn more about your CBC test results include:

  • What does my CBC indicate about my health?
  • Were any results from the test abnormal? If so, which levels were abnormal?
  • Are there any diagnoses to be made based on my CBC results?
  • Will any follow-up tests be needed based on my CBC results?
  • Given my CBC results, is there anything that you would suggest I do to improve my health?
  • Red Blood Cell Count (RBC) Test
    Learn More
  • Hematrocit Blood Test
    Learn More
  • White Blood Cell Count (WBC Blood Test)
    Learn More
  • Platelet Count (PLT) Blood Test
    Learn More
  • Reticulocyte Count Test
    Learn More
  • Blood Smear
    Learn More
  • Iron Test
    Learn More
  • Hemoglobin Blood Test
    Learn More


  • National Heart, Lung, and Blood Institute: Blood Tests
  • Leukemia and Lymphoma Society: Understanding Blood Counts
  • National Library of Medicine: Blood Disorders (Hematological Diseases)
  • National Library of Medicine: Bone Marrow Diseases


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National Heart, Lung, and Blood Institute. Blood Tests. March 24, 2022. Accessed September 28, 2022. https://www.nhlbi.nih.gov/health-topics/blood-tests

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Tefferi A. Approach to the Patient With Thrombocytosis. In: Leung LLK, ed. UpToDate. Updated August 19, 2022. Accessed September 28, 2022.  https://www.uptodate.com/contents/approach-to-the-patient-with-thrombocytosis

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Complete blood count (CBC) – decoding of indicators

For those interested, we talk in detail about the complete blood count (CBC), decipher the main indicators, give norms for children and adults, and also talk about possible causes of deviations. For prices for blood tests and all other types of tests, see the “Services” section of our website.

Complete blood count is the most common test and is widely used for screening for most diseases. Changes occurring in the blood most often reflect the processes occurring in the whole organism.

The best biomaterial for this test is blood taken from a vein (venous blood). It is when taking blood from a vein that it is possible to achieve minimal traumatization and activation of cells, admixture of tissue fluid, and it is possible to repeat and/or expand the analysis.

In some cases, however, it may be necessary to use capillary blood (eg neonates, patients with hard to reach veins, etc.).

The interpretation of the result of a blood test must be made by a physician, taking into account the patient’s condition, medical history and clinical picture.

Be aware that normal values ​​vary between children and adults, men and women, and may vary from laboratory to laboratory.

Hemoglobin concentration (HGB) . The normal content of hemoglobin in human blood is considered: in men – 130-160 g / l (lower limit – 120, upper limit – 180 g / l), in women – 120-150 g / l; in children, the normal level of hemoglobin depends on age and is subject to significant fluctuations. So, in children 1-3 days after birth, the normal level of hemoglobin is maximum and amounts to 145-225 g / l, and by 3-6 months it decreases to a minimum level of 95-135 g / l, then from 1 year to 18 years there is a gradual increase in the normal level of hemoglobin in the blood.

Hemoglobin is the main component of red blood cells, it is the carrier of oxygen from the lungs to the tissues. The hemoglobin level can change in clinically healthy individuals, since some factors, such as altitude, smoking, pregnancy, dehydration, or vice versa, increased fluid intake, physical activity, can affect the value of this indicator. A decrease in hemoglobin concentration may indicate the presence of anemia, which requires mandatory additional examination to determine the cause of the disease and select the correct treatment.

Red blood cells (RBC) . The average hemoglobin content for men is 13.3-18 g% (or 4.0-5.0 1012 units), for women – 11.7-15.8 g% (or 3.9-4.7 1012 units). The hemoglobin level is the percentage of hemoglobin in 1 gram of red blood cells.

Erythrocytes are red blood cells in the form of a biconvex disk, they contain hemoglobin. The main function of erythrocytes is to provide gas exchange, transport oxygen to tissues and organs. Also, these cells are involved in maintaining the acid-base state, affect the rheological properties (viscosity) of the blood, participate in immune processes by interacting with antibodies, circulating immune complexes.

The number of red blood cells in the blood 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 main diagnostic criteria for anemia. Also, a decrease in the level of these cells can be observed during pregnancy, blood loss, overhydration and always requires additional examination to rule out life-threatening diseases. An increase in the number of red blood cells – erythrocytosis – can be observed with polycythemia, lung diseases, heart defects, increased physical activity, when staying at high altitudes, Cushing’s syndrome, pheochromocytoma, hyperaldosteronism, dehydration, alcoholism, smoking.

If there are changes in the erythrocyte count, a consultation with a therapist is necessary, who will conduct an examination and prescribe the necessary additional examinations to identify the exact cause and correct treatment.

Hematocrit (HCT) is the ratio of the volume of formed elements and blood plasma. Normally, the hematocrit of a man is 0.40–0.48, and that of a woman is 0.36–0.46. In newborns, the hematocrit is about 20% higher, and in young children it is about 10% lower than in an adult.

Increased level:

  • Erythrocytosis
  • Polycythemia
  • Burn disease
  • Shock
  • Dehydration
  • contraceptives)


  • Anemia
  • Pregnancy (second trimester)
  • Hydration
  • Drugs (amphotericin B, ibuprofen, penicillin)

Leukocytes (WBC) (white blood cells). In the blood of an adult, leukocytes are 1000 times less than erythrocytes, and on average their number is 4-9109/l. In newborn children, especially in the first days of life, the number of leukocytes can vary greatly from 9 to 30 109 / l. In children aged 1-3 years, the number of leukocytes in the blood ranges from 6.0-17.0 109/l, and at 6-10 years old it ranges from 6.0-11.0 109/l.

The content of leukocytes in the blood is not constant, but changes dynamically depending on the time of day and the functional state of the body. Thus, the number of leukocytes usually slightly increases in the evening, after eating, as well as after physical and emotional stress. They play a major role in the specific and nonspecific protection of the body from external and internal pathogenic agents, as well as in the implementation of typical pathological processes (for example, inflammation) .

All types of leukocytes are capable of active movement and can pass through the capillary wall and penetrate into the intercellular space, where they absorb and digest foreign particles.

If a lot of foreign bodies have penetrated into the body, then phagocytes, absorbing them, greatly increase in size and eventually collapse. This releases substances that cause a local inflammatory reaction, which is accompanied by swelling, fever and redness of the affected area.

Substances that cause an inflammatory reaction attract new leukocytes to the site of introduction of foreign bodies. Destroying foreign bodies and damaged cells, leukocytes die in large quantities. The pus that forms in the tissues during inflammation is an accumulation of dead white blood cells.

The leukocyte formula is the percentage of different types of leukocytes. Leukocytes differ in origin, function and appearance.

Neutrophils (NEUT) . Mature segmented neutrophils are normally the main type of leukocytes circulating in human blood, accounting for 47% to 72% of the total number of blood leukocytes. Another 1-5% are normally young, functionally immature neutrophils, which have a rod-shaped solid nucleus and do not have the segmentation of the nucleus characteristic of mature neutrophils – the so-called stab neutrophils.

The main function of neutrophils is to protect the body from microorganisms. These cells play a very important role in protecting the body from bacterial and fungal infections, and a relatively minor role in protecting against viral infections. In antitumor or anthelmintic protection, neutrophils practically do not play a role.

An increase in neutrophils (neutrophilosis) can be a sign of an acute and (less often) chronic infectious disease, oncological process, inflammatory process, autoimmune diseases, observed in the postoperative period, with increased physical exertion.

A decrease in the level of neutrophils (neutropenia) may indicate the presence of a blood cancer, bone metastases, radiation sickness, aplastic anemia, it happens when taking certain medications, with anaphylactic shock, starvation, autoimmune diseases.

Monocytes (MONO) . Normally, monocytes make up from 3% to 11% of the total number of leukocytes in the blood. These are the largest peripheral blood cells, they are macrophages, that is, they can absorb relatively large particles and cells or a large number of small particles and, as a rule, do not die after phagocytization (monocytes may die if the phagocytosed material has any cytotoxic properties for the monocyte). In this they differ from microphages – neutrophils and eosinophils, which are capable of absorbing only relatively small particles and, as a rule, die after phagocytosis. Compared to neutrophils, monocytes are more active against viruses than bacteria, and are not destroyed during the reaction with a foreign antigen, therefore, pus does not form in the foci of inflammation caused by viruses. Also, monocytes accumulate in the foci of chronic inflammation.

An increase in the number of monocytes can be caused by infections of a viral, parasitic, bacterial nature and caused by protozoa, autoimmune and oncological diseases, leukemia.

Basophils (BASO) are normal: 0 – 1%. These are very large granulocytes: they are larger than both neutrophils and eosinophils. Basophil granules contain large amounts of histamine, serotonin, leukotrienes, prostaglandins, and other mediators of allergy and inflammation. These cells are involved in delayed-type hypersensitivity reactions, inflammatory and allergic reactions, and regulation of vascular wall permeability.

An increase in the level of basophils can be observed in allergic diseases, rheumatism, leukemia, myelofibrosis, polycythemia.

Eosinophils (EO) make up 1 to 5% of white blood cells. These cells, like neutrophils, are capable of phagocytosis, and they are microphages, that is, they are capable, unlike macrophages, of absorbing only relatively small foreign particles or cells. However, the eosinophil is not a “classical” phagocyte; its main role is not in phagocytosis. Their main property is the expression of Fc receptors specific for Ig E. Physiologically, this is manifested in the powerful cytotoxic, rather than phagocytic, properties of eosinophils, and their active participation in antiparasitic immunity. However, increased production of class E antibodies can lead to an immediate type of allergic reaction (anaphylactic shock), which is the main mechanism of all these types of allergies.

Increased levels, eosinophilia, may be a sign of allergic diseases: bronchial asthma, pollinosis, allergic dermatitis, allergic rhinitis, drug allergy.

Also, an increase in the level of these cells may indicate the invasion of parasites: ascariasis, toxocariasis, trichinosis, echinococcosis, schistosomiasis, filariasis, strongyloidiasis, opisthorchiasis, hookworm, giardiasis.

Eosinophilia can be associated with various oncological processes, immunodeficiency, connective tissue diseases (periarteritis nodosa, rheumatoid arthritis).

A decrease in the number of eosinophils, eosinopenia, may be in the first stages of the inflammatory process, with severe purulent infections, shock, sepsis, eclampsia during childbirth, with intoxication with chemical compounds and heavy metals.

Changes in the leukocyte formula should be interpreted by a doctor, since only a specialist (therapist, pediatrician, surgeon, allergist, traumatologist, otolaryngologist, gynecologist, neurologist, etc.) can correctly assess the analysis indicators, prescribe additional examinations if necessary (biochemical blood test , examination for infections, allergies, ultrasound) to establish the correct diagnosis and prescribe treatment.

Platelets (PLT) are small (2-4 µm) non-nucleated, flat, colorless blood cells. The physiological plasma concentration of platelets is 180-360.109 platelets per liter. The main function of these elements is the formation of a platelet aggregate, a primary plug that closes the site of damage to the vessel and provides its surface to accelerate the key reactions of plasma coagulation. Thus, platelets provide normal permeability and resistance of the walls of microvessels.

A decrease in the number of platelets in the blood can lead to bleeding. An increase in their number leads to the formation of blood clots (thrombosis), which can block blood vessels and lead to pathological conditions such as stroke, myocardial infarction, pulmonary embolism, or blockage of blood vessels in other organs of the body.

Platelet deficiency or disease is called thrombocytopathy, which can be either a decrease in the number of platelets (thrombocytopenia), a violation of the functional activity of platelets (thrombasthenia), or an increase in the number of platelets (thrombocytosis). There are diseases that reduce the number of platelets, such as heparin-induced thrombocytopenia or thrombotic purpura, which usually cause thrombosis instead of bleeding.

A change in the number of platelets requires an additional study of the blood coagulation system (coagulogram) as prescribed by the attending physician.

ESR or erythrocyte sedimentation rate is a non-specific laboratory blood indicator that reflects the ratio of plasma protein fractions. A change in ESR can serve as an indirect sign of a current inflammatory or other pathological process. Also, this indicator is known as the “Erythrocyte sedimentation reaction”, ROE . Normally, the ESR value in women is in the range of 2-15 mm/hour, and in men – 1-10 mm/hour.

Most often, an increase in ESR is associated with acute and chronic infections, immunopathological diseases, infarcts of internal organs.

Although inflammation is the most common cause of accelerated erythrocyte sedimentation, an increase in ESR can also be due to other, including not always pathological, conditions. ESR can also increase with malignant neoplasms, with a significant decrease in the number of red blood cells, during pregnancy, while taking certain medications. A sharp increase in ESR (more than 60 mm / h) usually accompanies such conditions as a septic process, autoimmune diseases, malignant tumors accompanied by tissue breakdown, leukemia. A decrease in the erythrocyte sedimentation rate is possible with hyperproteinemia, with a change in the shape of erythrocytes, erythrocytosis, leukocytosis, DIC, hepatitis.

Despite its non-specificity, the determination of ESR is still one of the most popular laboratory tests for establishing the fact and intensity of the inflammatory process.

A change in the indicator requires specialist advice, correct interpretation in accordance with the clinical picture of the patient’s condition, and other changes in the blood test. Most often, the doctor conducts additional examinations (ultrasound, specialist consultations) to identify the cause and possible disease.

Complete blood count – deciphering the UAC indicators

By: Administrator | Tags: blood test, UAC, complete blood count, decoding of UAC indicators | Comments:
0 | February 18, 2020

Blood is the most important matter of the body, performing regulatory, nutritional, excretory, respiratory and other functions.

Blood is 50% plasma. This is a multicomponent liquid, which includes microelements, enzymes and hormones. The other 50% belong to blood cells, each with its own unique role.

Any disease, whether of an inflammatory, oncological, autoimmune or metabolic nature, affects the qualitative and quantitative composition of the blood. And therefore, the diagnosis of diseases begins precisely with the appointment of a general blood test.

Definition and purpose of prescribing

Complete blood count (CBC) is a laboratory diagnostic method for assessing the state of the body and finding the source of pathology. This analysis can be prescribed by a doctor of any specialty. In what cases is KLA prescribed:

  1. For prophylaxis at medical examinations. The composition of the blood is relatively constant and rarely goes beyond the normal range in a healthy person. And some diseases may not affect well-being for a long time, and then preventive delivery will be the reason for a subsequent examination.
  2. When the first symptoms of malaise appear. The analysis in this case may allow to determine the nature of the disease, the degree of intensity of inflammation or an allergic reaction.
  3. KLA may be re-assigned to track the course of the disease after a certain time. Also to evaluate the effectiveness of the therapy.

What indicators are included in the UAC

The complete blood count includes the following indicators: erythrocytes, hemoglobin, leukocytes, color index, hematocrit, reticulocytes, platelets, ESR.

In some laboratories, the leukocyte formula is signed by default; in some, a doctor’s note is required. It includes the following indicators: eosinophils, basophils, stab and segmented neutrophils, lymphocytes, monocytes.

Below is a table of norms for a complete blood count:

Indicator Lab designation Norma (women) Norma (men) Unit
Erythrocytes RBC 3.8-4.5 4.4-5.0 10 12 /l
Hemoglobin HGB 120-140 130-160 g/l
Leukocytes WBC 4.0-9.0 4.0-9.0 10 9 /l
Color index CPU 0.8-1.0 0.8-1.0
Hematocrit HCT 35-45 39-49%
Reticulocytes RET 0. 2-1.2 0.2-1.2%
Platelets PLT 170.0-320.0 180.0-320.0 10 9 /l
ESR ESR 2-15 1-10 mm/hour
Leukocyte formula:
Basophils BAS 0-1 0-1%
Eosinophils EO 0.5-5 0.5-5%
Myelocytes 0 0%
Metamyelocytes 0 0%
Neutrophils, stab NEUT 1-6 1-6%
Segmented neutrophils NEUT 47-67 47-67%
Lymphocytes LYM 18-40 18-40%
Monocytes MON 3-11 3-11%

In some places, the CBC norm for adults differs from that for children.

For example, the norm of hemoglobin in a child is 110-145 g / l, leukocytes 5.0-12.0 10 9 / l, the content of lymphocytes can be in the range of 26-60%. The remaining parameters of the blood test correspond to the reference values ​​for adults.

By order of the Ministry of Health, in the first year of life, a child’s blood is taken for general analysis 4 times, then at 1 year for 6 months, and then annually, starting from two years. Such measures are necessary for the early detection of blood diseases, anemia, and infections.

Deciphering the complete blood count

Below are the most basic indicators of the KLA, their functions in the body, the reasons for the deviation in the direction of increase or decrease.


These are small elastic cells containing hemoglobin in their cytoplasm. Due to their elasticity, they easily pass through vessels of any caliber. They are produced in the bone marrow, the viability of one cell is about 3-4 months.

Erythrocytes perform the following function: they carry oxygen from the lungs to all human tissues and organs, and on the way back from the tissues to the lungs they bring carbon dioxide. All this happens by attaching gases to the hemoglobin of the erythrocyte.

The norm of erythrocytes when deciphering analyzes is on average from 3.8 to 5.0 10 12 / l

  • an increase in erythrocytes in the general blood test is possible with dehydration of the body due to vomiting and diarrhea, diseases of the blood system (erythremia, Wakez disease) , cardiac and respiratory failure.
  • their decrease can be with blood loss, leukemia and lymphomas, congenital defects in hematopoiesis, hemolytic anemia, oncology, insufficient intake of protein, iron and vitamins.

It should be remembered that the rate of erythrocytes, as well as other indicators, may differ in different laboratories. In which, moreover, errors are not excluded. Therefore, a borderline result does not always indicate a serious illness.


Hemoglobin is an iron-containing protein found in red blood cells. It is due to it that the function of gas exchange between the lung tissue and all cells of the body is performed. A deviation in the level of hemoglobin from the norm can cause a person to feel unwell, his weakness, fatigue. This is due to a lack of oxygen in the organs, including the brain.

The normal content of hemoglobin in the general blood test is on average 120-160 g/l, depending on the gender and age of the subject.

  • An increase in hemoglobin may occur due to dehydration due to diabetes mellitus, vomiting and diarrhea, due to heart failure, diuretic overdose, pulmonary insufficiency, heart defects, diseases of the blood and urinary system.
  • A decrease in hemoglobin in the general blood test is possible with anemia of various origins and other blood diseases, blood loss, insufficient intake of protein, vitamins, iron


These are white blood cells synthesized in the bone marrow. They perform the most important protection function in the body, aimed at foreign objects, infections, foreign protein molecules. They are also able to dissolve damaged body tissue, which is one of the stages of inflammation. The viability of these cells varies from a few hours to several years.

The norm of leukocytes in the general blood test corresponds to 4.0-9.0 10 9 /l.

  • An increase in leukocytes in the KLA is possible due to physiological errors (pregnancy, blood donation after meals, heavy physical exertion, after vaccinations), inflammatory processes of a systemic or local nature, extensive injuries and burns, active autoimmune diseases, in the postoperative period, with oncology, leukemia and leukemia.
  • If leukocytes are reduced when deciphering a blood test, the presence of viral infections, systemic autoimmune diseases, leukemia, radiation sickness, hypovitaminosis is acceptable. The use of cytostatics and steroids may also affect.

Color index

The color index (CPI) is determined by calculation using a special formula. It shows the average concentration of hemoglobin protein (Hb) in one erythrocyte.

Normal CPU is 0.8-1.0, without units.

  • Its increase may indicate the presence of hyperchromic anemia (vitamin D deficiency).
  • Reduction is possible with iron deficiency anemia, posthemorrhagic anemia, leukemia and lymphoma, chronic diseases of the organs.


This indicator reflects the ratio of blood cells (leukocytes, erythrocytes, platelets) to the total blood volume. The analysis is carried out by centrifugation or using analyzers.

Normal hematocrit averages 35-50%.

  • An increase may indicate erythremia, respiratory failure, heart failure, dehydration due to diabetes and diabetes insipidus, diarrhea and vomiting.
  • Decreased hematocrit may be due to anemia, erythrocytopenia, renal failure, pregnancy (third trimester).


These are the precursors of erythrocytes, their intermediate form. They perform the function of gas exchange, as well as red blood cells, but with less efficiency. In a healthy person, reticulocytes, when deciphered, make up 0.2-1.2% of the total number of erythrocytes.

  • May be increased with post-hemorrhagic restoration of hematopoiesis, when moving to a mountainous area or in the treatment of anemia.
  • Decreased reticulocytes in the general blood test with reticulocytopenia (slow hematopoiesis in the bone marrow, leading to anemia).


These are small, flat, colorless blood cells. They perform several important functions – they participate in blood coagulation, form a platelet thrombus, regulate the tone of the vascular wall, and nourish the capillaries.

In the general blood test, the platelet rate is 180-320 10 9 /l.

  • An increase in platelets when deciphering the analysis is possible with splenectomy (removal of the spleen), exacerbation of chronic autoimmune diseases, anemia of various origins, inflammatory processes, in the postoperative period, the third trimester of pregnancy, with oncology, erythremia.
  • Reduced platelets in the KLA with hemophilia, drug thrombocytopenia, systemic lupus erythematosus, viral and bacterial infections, aplastic anemia, Evans syndrome, autoimmune thrombocytopenic purpura, renal vein thrombosis.


Erythrocyte sedimentation rate (ESR) is an indicator calculated during the laboratory test. Under the influence of anticoagulants, the erythrocyte sedimentation time is calculated, which depends on the protein composition of the plasma.

This is a highly sensitive indicator, it normally averages from 1 to 15 mm per hour.

  • Increases in physiological conditions (pregnancy, menstruation), infectious diseases, malignant neoplasms, systemic autoimmune diseases, kidney diseases, in the postoperative period, injuries and burns.
  • Decreases with astheno-neurotic syndrome, recovery from infection, cachexia, long-term use of glucocorticoids, blood clotting disorders, high blood glucose concentrations, with craniocerebral injuries, taking NSAIDs, immunosuppressants, antibiotics.


This is the largest subspecies of leukocytes, which, depending on the maturity of the cells, is divided into the following groups – young neutrophils, stab and segmented.

They perform an antimicrobial function, are capable of phagocytosis, and participate in the inflammatory response.

The norm of neutrophils in the blood test is stab 1-6%, segmented 47-67%.

  • An increase in neutrophils when deciphering a blood test is possible under physiological conditions (sun and temperature exposure, stress, pain, etc.), with past infections, diseases of the bone marrow, oncology, taking certain medications, ketoacidosis, poisoning with poisons and alcohol , with parasitosis, allergies, hyperglycemia.
  • Decreased in post-chemotherapy, HIV/AIDS, aplastic anemia, chronic infectious disease, radiation exposure, vitamin B12 and folic acid deficiencies.


This is also a subspecies of leukocytes, represented as T-lymphocytes, B-lymphocytes, K- and NK-lymphocytes.

All of them participate in acquired immunity, synthesize antibodies, destroy not only foreign, but also their own pathological cells (oncological).

The norm of lymphocytes when decoding in the KLA is 18-40%

  • An increase in the general blood test can be with viral infections (mononucleosis, viral hepatitis and others), toxoplasmosis, blood diseases (chronic and acute lymphocytic leukemia, lymphoma, leukemia), with arsenic, lead poisoning, taking levodopa, narcotic painkillers.
  • Lymphocytes decrease in tuberculosis, HIV, blood diseases (lymphogranulomatosis, aplastic anemia), terminal renal failure, oncological diseases in the terminal stage and during treatment with radio and chemotherapy, taking glucocorticoids.


This is a type of the largest leukocytes, also synthesized in the bone marrow. They are able to phagocytize (absorb) viruses, bacteria, tumor and parasitic cells. Regulate hematopoietic function, participate in blood coagulation.

The norm of a blood test for the content of monocytes is 3-11%.

  • an increase in monocytes during decoding indicates viral, bacterial (tuberculosis, syphilis, brucellosis), fungal and parasitic infections, inflammation in the regeneration stage, systemic autoimmune diseases (systemic lupus erythematosus, rheumatoid arthritis), leukemia.
  • a decrease in monocytes in a blood test is possible with purulent-inflammatory processes, aplastic anemia, in the postoperative or postpartum period, when taking steroids.

Preparing for blood donation

Do not eat, drink tea or coffee, or smoke before taking a complete blood count. On the eve it is necessary to exclude the intake of alcohol, fatty foods. Blood donation is most often done in the morning, blood can be taken from a capillary or from a vein.

Complete blood count can reflect the disease in the very early stages, but the study is highly sensitive. Therefore, for an adequate diagnosis, it is worth following all the recommendations before donating blood.