Blood test according to the decoding formula. Blood test with leukocyte formula. Red blood cells in a general blood test and their characteristics

One of the components of a blood test is the leukocyte formula. Doctors recommend its determination for any pathology, since it is sensitive to many pathologies. In the article we will analyze all possible changes in the number of leukocytes and what they mean.

Types of leukocytes

A general blood test consists of several indicators. All of them are reflected in their own units of measurement, with designations in Latin letters.

Therefore, when receiving a blood test (leukogram), deciphering the values ​​will be useful to any person:

The leukocyte formula is recorded separately. It reflects the ratio of white blood cells to each other. This is important for clinical diagnosis, since all white blood cells are not the same.

There are several varieties of them, which differ in their functions in the human body:

• Neutrophils;
• Lymphocytes;
• Monocytes;
• Eosinophils;
• Basophils.

Neutrophils

One of the most versatile cells. Activated by any inflammation, no matter bacterial or viral. Neutrophils destroy any substances foreign to the body, releasing chemical components that attract other inflammatory cells. Therefore, any inflammatory reaction is essentially triggered by neutrophils.

Neutrophil cells are also divided according to their degree of maturity:

• Myelocytes and metamyelocytes- very young, juvenile cells that do not perform any functions. A healthy person does not have them in the blood.
• Rod- maturing cells that are always found in the blood. Their number increases sharply during the onset of infection.
• Segmented- the oldest, most mature cells. They perform all the functions of protecting the body inherent in neutrophils. Segmented neutrophils are the very last stage of myelocyte development.

Lymphocytes

These are the cells that carry out the second stage of the immune response. They come to the site of inflammation, reacting to chemicals released by neutrophils.

There are several types of lymphocytes:

• B lymphocytes– create antibodies to viral and bacterial infections.
• Helper and killer T lymphocytes– trigger the work of B-lymphocytes and independently destroy viral cells.
• Natural killer cells– capable of destroying cells that have been infected by a virus or that have undergone tumor changes.

Monocytes

Similar in function to neutrophils. Main job of monocytes– destroy foreign material. They perform their task using phagocytosis.

This is the process of engulfing a bacterium, virus or any other pathogen by a monocyte. Inside the cell, this element dies, giving monocytes information about its structure. In the future, this will help B-lymphocytes produce antibodies specifically to this pathogen.

Eosinophils and basophils

These are the cells involved in allergic reactions. Their number increases sharply if the human body develops an allergy to any substance.

It is due to the chemical elements that eosinophils secrete that a person develops symptoms of an acute allergic reaction:

• The face swells;
• A cough or runny nose appears;
• The skin turns red;
• A rash appears.

Functions of leukocytes

It’s not for nothing that the leukoformula consists of several components. Each of these cells is important in providing the body with healthy immunity. It all starts with the entry of a bacteria or virus into the human body. The pathogenic microbe is absorbed by the neutrophil, which digests it - phagocytosis.

After phagocytosis, the neutrophil retains the microbial particle, showing it to lymphocytes. T lymphocytes and B lymphocytes work together to organize an attack on the pathogen. B cells create a host of antibodies that are ideally suited to this bacterium. Only such joint actions provide an immune response to any infection. That is why the ratio of leukogram cells is so important.

Normal leukogram values

In each laboratory, different values ​​can be accepted as normal, depending on the technology and reagent used by laboratory technicians. Therefore, follow-up analysis must be performed in one laboratory. This will allow you to maintain the correctness of the values ​​and clearly trace the dynamics.

But there are average criteria that can be used if the laboratory has not provided its data.

The normal number of cells depends greatly on the gender and age of the person.

How is the analysis carried out?

Blood can be collected in two ways to determine the number of leukocytes:

• Capillary- from a finger.
• Venous– from a peripheral vein.

Analysis indicators taken in different ways can vary even within one person. But usually these changes do not exceed normal values. The method of counting has always previously been to view the blood under a microscope. It is carried out by a laboratory assistant, counting the number of cells in the fields of view under a microscope.

The calculation is carried out for 100 cells, so it is convenient to display the final result as a percentage. Before counting neutrophils or other cells, the field of view is mentally divided into 3 sections from one edge to the other.

Today, many laboratories use an automatic analyzer. This is a device that counts all possible cells that it encounters.

When using a hematology analyzer, you can view more cells in a short time. But in controversial cases, preference is given to viewing under a microscope by a laboratory assistant. A person can detect minor differences in the appearance of cells, which may indicate pathology.

Why is the leukoformula determined?

A large number of leukoformula indicators allows it to respond to many diseases. A well-calculated analysis in normal and pathological conditions will be of great help to the doctor.

When a doctor refers you to determine the number of leukocytes, he has several goals:

• Help in making a diagnosis;
• Determination of the severity or activity of the process;
• Dynamics of recovery;
• Reaction or lack thereof to medications;
• Early detection of complications.

Changes in quantity and ratio in the leukogram

When calculating the percentage of neutrophil cells, the ratio of mature and young forms of leukocytes is necessarily displayed. This allows you to understand the severity of the process and its severity.

With an increase in the number of band and young cells in the analysis, they speak of a shift in the leukocyte formula to the left, since these cells are located on the left in the form. This indicates an active immune response. In some cases, the appearance of the most immature cells in the peripheral blood may indicate cancer.

Table of the ratio of neutrophil forms as a percentage of the total number of white blood cells.

In controversial cases or when conducting clinical studies, the determination of the leukocyte intoxication index (LII) can be used. This is the ratio of immature forms of neutrophils that appear during acute inflammation to other cells - lymphocytes, monocytes, eosinophils.

Index values ​​are calculated depending on age and gender. The approximate index number is 0.6.

Causes of increase or decrease in leukocytes

An increase in the number of neutrophils occurs when:

• Bacterial infections– sore throat, pyelonephritis, pneumonia;
• Intoxication of any nature;
• Taking glucocorticosteroids– prednisolone;
• Burn disease;
• Gangrene, heart attack.

A decrease in the number of neutrophils accompanies:

• Severe bacterial infections– brucellosis, tuberculosis;
• Viral infections– measles, rubella;
• Effects of toxins on the bone marrow;
• Radiation sickness;
• Autoimmune diseases.

The main reason for the change in the number of lymphocyte cells– various types of infections. B lymphocytes mature in the bone marrow, and T lymphocytes mature in the thymus. This difference emphasizes that their functions are different. But in the analyzes it does not matter which fraction is elevated. The laboratory examines the total lymphocyte count.

Lymphocytosis, or an increased number of lymphocytes, occurs when:

• Chronic bacterial infections– tuberculosis, syphilis, brucellosis;
• Acute viral diseases– flu, chickenpox, measles;
• Tumors of the blood system– lymphomas;
• Hormonal dysfunctions– hypothyroidism;
• Macrocytic anemias– folate deficiency;
• Autoimmune pathologies– systemic lupus erythematosus.

A reduced number of lymphocytes or lymphocypenia accompanies:

• Primary immunodeficiencies– DiGeorge syndrome;
• Secondary immunodeficiencies- HIV infection;
• Taking glucocorticosteroids– prednisolone;
• Acute bacterial infections– streptococcal pneumonia;
• Toxic effects on bone marrow– irradiation, heavy metals.

Monocytes have virtually no clinical significance when considered individually. Therefore, their changes are usually assessed in combination with other leukocyte parameters.

Monocytes usually increase when:

A decrease in the number of monocytes practically does not occur without general leukocytopenia. Therefore, it has no diagnostic value. It is worth mentioning infectious mononucleosis. This is a viral infection, the main criterion of which is the detection of mononuclear cells in the blood.

These are cells similar to monocytes, but are pathological. In a healthy person, detection of mononuclear cells in the blood is unacceptable.

Eosinophils and basophils are criteria for allergic reactions and some infectious diseases. The estimate of their number also strongly depends on the total number of leukocytes in the blood test.

Low eosinophils accompany:

• Taking corticosteroid medications;
• Some severe infections such as typhoid fever.

Video: Decoding a blood test

It was and remains the most common and frequently prescribed diagnostic method. It is taken many times throughout life and for any diagnosis. This analysis allows you to evaluate the functioning of all systems and organs in the body.

It includes a qualitative and quantitative description of the formed elements, their relationship to the liquid part of the blood (plasma). Making a diagnosis based on a general blood test alone is difficult, but this procedure allows you to determine the direction for further examination.

Blood consists of formed elements and plasma. The quantity of these elements, their ratio, concentration and quality indicators form the basis of a blood test. With such a diagnosis, the quantity is assessed, as well as the level of and (erythrocyte sedimentation rate).

The standard is a general blood test with a formula, the decoding of which implies the presence, that is, the ratio of different types of leukocytes (neutrophils, monocytes, basophils,). These are standard indicators, but they may not be included in the summary analysis, so the necessary items are noted when assigning.

The positive aspects of such an examination are simplicity and accessibility, quick results (within 1-2 days), low price (if you have a referral, it is carried out free of charge), and high information content.

But it is worth considering that blood counts largely depend on various factors: nutrition, environment, gender, age and even race.

• Prevention. As a preventative measure, you can donate blood once every six months or year. Even in cases where nothing worries you, diagnostics will not be superfluous. It helps to suspect diseases at the earliest stages, when symptoms have not yet appeared. This significantly increases the effectiveness of treatment.
• Diagnosis of diseases. When diagnosing any diseases (heart, kidneys, liver and other organs), as well as any infections, it is recommended to donate blood for analysis.
• Suspicion of blood diseases. The analysis allows you to determine whether there are abnormalities in the composition of the blood, deviations in the quantity and quality of formed elements, which can lead to suspicion of bone marrow disease.
• Pregnancy. During pregnancy, a woman donates blood for examination constantly. The closer to childbirth, the more often the examination is carried out. In the early stages, especially with toxicosis, a general blood test is also necessary. The number of platelets (tendency to thrombosis or bleeding) and hemoglobin level (risk of oxygen starvation of the fetus) are especially important.

Preparation and procedure

The blood collection procedure is familiar and understandable to everyone. The nurse takes venous (capillary) blood, numbers it, documents it, and then the material is delivered to the laboratory, where it is examined within 24 hours.

All that is required of the patient is to come to the laboratory at the appointed time with a coupon and a referral. Before giving a referral, the doctor will tell you the necessary preparation rules. They should not be neglected.

The composition of the blood tends to change and react to everything that happens to the body. For the result to be reliable, you need to follow some rules. Many people believe that the only rule is to fast for 8-10 hours before visiting the laboratory.

But other factors may also influence the result of the analysis:

1. Food. Even if the patient comes to the laboratory with an empty stomach, what he ate the day before can affect the result. For example, an abundance of protein or fatty foods eaten during the day before the test can cause the blood serum to be cloudy and unsuitable for examination.
2. Drugs. Taking medications has a direct impact on the composition and. You should inform your doctor about all medications you take (including oral contraceptives, vitamins and dietary supplements). He will advise which ones need to be canceled and for how long.
3. Physical exercise. Before taking the test, it is not recommended to engage in physical exercise, even for those who are used to it. Physical activity can cause hormonal changes and affect the results.
4. Emotional condition. Stress also affects the body. Strong emotional stress negatively affects the functioning of all systems and organs, and the result of the analysis may be poor.
5. Bad habits. Smoking and alcohol affect metabolism. It is generally advisable to give up alcohol 3 days before visiting the laboratory, and quit smoking at least on the day of blood sampling.
6. Times of Day. The analysis is prescribed in the morning not only because it is easier to observe hunger. The body has certain daily rhythms. During the day, blood counts may change depending on environmental factors. To standardize reference values, it is recommended to donate blood only in the morning, except in emergency cases.

Indicators and their norm

A detailed blood test includes a large number of indicators. Each indicator has its own reference values, normal limits. An increase or decrease in indicators, going beyond the boundaries of this norm may be a sign of some pathology.

The main indicators of a general blood test include the following:

Even if you know the reference values, it is quite difficult to interpret the analysis result yourself. All indicators need to be taken into account together. In addition, a deviation from the norm of one or another indicator can be interpreted differently depending on gender, age, cycle time (in women) and other factors.

Very often, in case of any violations, a deviation from the norm is observed in several indicators at once. It is problematic to make an accurate diagnosis based on a blood test alone, so the doctor identifies certain disorders and refers them for further examination.

Using blood parameters, the following conditions and diseases can be identified:

1. . Anemia has many types and forms. Most often it is observed when hemoglobin levels decrease, when all organs and tissues experience oxygen starvation. Anemia is usually spoken of when the hemoglobin level falls below 90-100 g/l. The causes of anemia can be physiological (heavy exercise, dehydration) or pathological. Leukocytosis. The reasons for the increase in white blood cell levels may be different. Physiological causes include pregnancy and childbirth, large amounts of protein foods, heavy physical activity, and PMS. Pathological causes include inflammatory processes of microbial and non-microbial origin, leukemia, cancer, burns and prolonged bleeding.
2. Thrombocytosis. A high level of platelets is dangerous because it can lead to the formation of blood clots and blockage of blood vessels and arteries. The number of platelets in the blood increases sharply with anemia with iron deficiency, with some infections and heavy bleeding, and oncology.

You can learn more about the leukocyte formula from the video:

Each of these conditions can be interpreted differently. For example, leukocytosis can be caused by a variety of infections. You cannot prescribe treatment for yourself based on a blood test.

Complete Blood Count

A routine screening blood test, which includes determining the concentration of total hemoglobin, the number of red blood cells, leukocytes and platelets per unit volume, the hematocrit value and erythrocyte indices (MCV, MCH, MCHC).

Hemoglobin (Hb, Hemoglobin)

A respiratory pigment in the blood, which is contained in red blood cells and is involved in the transport of oxygen and carbon dioxide.

It consists of a protein part - globin - and an iron-containing part - heme. Hemoglobin is a protein of quaternary structure, formed by four polypeptide chains. Iron in heme is in divalent form. The hemoglobin content in the blood of men is slightly higher than that of women. In children of the first year of life, a physiological decrease in hemoglobin concentration is observed. An increase in hemoglobin concentration is observed when the blood thickens or is the result of an increase in the formation of red blood cells. A pathological decrease in hemoglobin content in the blood (anemia) may be a consequence of increased losses of hemoglobin during various bleedings, the result of accelerated destruction (hemolysis) of red blood cells, impaired formation of red blood cells, or other reasons. Anemia can be either an independent disease or a symptom of a general chronic disease (anemia of chronic diseases). As an independent disease, anemia develops with a lack of iron necessary for the synthesis of hemoglobin, with a deficiency of vitamins involved in the formation of red blood cells (mainly vitamin B12, folic acid), due to increased destruction of red blood cells in the peripheral blood (hemolytic anemia) or impaired formation of blood cells in the bone marrow for specific hematological diseases.

Hematocrit (Ht, Hematocrit)

The share (%) of all formed elements of the total blood volume.

This indicator, along with hemoglobin and red blood cells, is used to monitor the condition of the erythrocyte system. Hematocrit reflects the volume of all the formed elements in the blood - mainly red blood cells - and not their number. Changes in hematocrit do not always correlate with changes in total red blood cell count. For example, in patients in shock due to blood thickening, the hematocrit may be normal or even high, although due to blood loss, the total number of red blood cells may be significantly reduced. Therefore, the hematocrit value is not indicative when assessing the degree of anemia immediately after blood loss or blood transfusion.

Red Blood Cells (RBC)

Highly specialized anucleate blood cells containing hemoglobin, the main function of which is to transport oxygen from the lungs to the tissues and carbon dioxide from the tissues to the lungs.

Red blood cells are formed in the red bone marrow from stem cells. For the normal development of red blood cells, vitamin B 12, folic acid and a sufficient supply of iron are necessary. The formation of red blood cells is stimulated by erythropoietin, which is produced in the kidneys. The level of erythropoietin increases with tissue hypoxia. The average lifespan of red blood cells in the vascular bed is 120 days. Old cells are destroyed in the reticuloendothelial system and spleen, and the iron in hemoglobin is used to form new red blood cells. In one day, about 1% of red blood cells are renewed. An increase in the number of red blood cells above normal levels is called erythrocytosis, a decrease in the number of red blood cells (and hemoglobin) is called anemia,

For the differential diagnosis of anemia, in addition to determining the number of red blood cells, an assessment of their morphological characteristics is used. Normally, the diameter of erythrocytes is 7.2-7.5 microns, the volume is 80-100 fl. Red blood cells with a diameter of less than 6.7 microns and a volume of less than 80 fL are called microcytes; red blood cells with a diameter of more than 7.7 microns and a volume of more than 100 fl - macrocytes; red blood cells more than 9.5 microns in diameter are called megalocytes. Anisocytosis is the presence of red blood cells of different sizes in the blood. Depending on the predominance of certain forms of erythrocytes, they are distinguished: macrocytosis - a condition when 50% or more of the total number of erythrocytes are macrocytes (noted in B 12 and folate deficiency anemia, liver diseases); microcytosis - a condition in which 30-50% are microcytes (observed in iron deficiency anemia, microspherocytosis, heterozygous thalassemia, lead intoxication).

A more detailed description of the morphology of erythrocytes: changes in cell shape - poikilocytosis (presence of ovalocytes, schizocytes, spherocytes, target-like erythrocytes, etc.); presence of inclusions in erythrocytes; the content of nuclear forms of the erythroid series in peripheral blood; changes in cell coloring, etc. - if necessary, done by a hematologist when viewing a blood smear under a microscope. This information is reflected in the comments to the analysis.

Erythrocyte indices (MCV, MCH, MCHC)

Indices that allow quantitative assessment of the main morphological characteristics of red blood cells.

MCV - Mean Cell Volume

A quantitative indicator of the volume of red blood cells, a more accurate parameter than a visual assessment of the size of red blood cells when viewing a smear under a microscope. However, it should be taken into account that this parameter is an average value, and with pronounced anisocytosis, as well as in the presence of a large number of red blood cells with an altered shape, it does not sufficiently reflect the true size of the cells. Based on the MCV value, anemia is distinguished between microcytic, normocytic and macrocytic anemia. Microcytosis is characteristic of iron deficiency anemia, heterozygous thalassemia; macrocytosis - for B 12 - and folate deficiency anemia. Aplastic anemia can be normo- and macrocytic.

MCH - mean hemoglobin content in a red blood cell (Mean Cell Hemoglobin)

Calculated in absolute units, calculated by dividing the hemoglobin concentration by the number of red blood cells per unit volume. This parameter determines the average hemoglobin content in an individual red blood cell and is clinically similar to the color index. Based on this index, anemia can be divided into normo-, hypo- and hyperchromic.

MCHC - mean hemoglobin concentration in erythrocytes (Mean Cell Hemoglobin Concentration)

It is calculated by the ratio of blood hemoglobin to hematocrit and reflects the saturation of red blood cells with hemoglobin. This is a concentration index that does not depend on cell volume, unlike MCH. MSHC is a sensitive indicator of changes in hemoglobin formation, in particular, in iron deficiency anemia, thalassemia, and some hemoglobinopathies (decrease in MSHC).

White Blood Cells (WBC)

Blood cells that ensure the recognition and neutralization of foreign components, the elimination of altered and decaying cells of the body's own, effectors of immune and inflammatory reactions, the basis of the body's antimicrobial defense.

The formation of leukocytes (leukopoiesis) takes place in the bone marrow and organs of the lymphatic system. This is a group of cells heterogeneous in origin, structure and properties. There are 5 main types of leukocytes: neutrophils, eosinophils, basophils, lymphocytes, monocytes, which perform different functions. Differential calculation of the content of these forms is carried out when prescribing a leukocyte formula test. The total number of leukocytes can change under the influence of various factors. A physiological increase in the level of leukocytes occurs after eating, after physical activity, and due to various types of stress. Reactive physiological leukocytosis is ensured by the redistribution of stationary and circulating neutrophils, the mobilization of mature leukocytes from the bone marrow. In women, a physiological increase in the number of leukocytes can be observed in the premenstrual period. The number of leukocytes normally increases in the second half of pregnancy and during childbirth.

A pathological increase in the number of leukocytes in the blood is observed under the influence of various infectious agents, poisons, under the influence of inflammatory factors and tissue necrosis, endogenous toxins. These factors stimulate the formation of leukocytes, which is a protective reaction of the body.

With some viral infections, under the influence of cytotoxic drugs, leukopenia can develop - a decrease in the level of blood leukocytes. Significant changes in the number of leukocytes are observed in specific hematological diseases, which can manifest themselves as a significant increase in the content of leukocytes, or a sharp decrease in their number. Important diagnostic information in these cases is provided by determining the differential leukocyte formula by viewing a blood smear under a microscope.

Platelet count

Formed elements of blood involved in ensuring hemostasis. Platelets are small anucleate cells, oval or round in shape; their diameter is 2-4 microns. Platelets are formed in the bone marrow from megakaryocytes. In a calm state (in the bloodstream), platelets have a disc-shaped shape. When activated, platelets acquire a spherical shape and form special projections (pseudopodia). With the help of such outgrowths, blood platelets can connect with each other (aggregate) and adhere to the damaged vascular wall (adhesion ability).

When stimulated, platelets have the property of releasing the contents of their granules, which contain coagulation factors, the enzyme peroxidase, serotonin, calcium ions - Ca 2 *, adenosine diphosphate (ADP), von Willebrand factor, platelet fibrinogen, platelet growth factor. Platelets can carry some coagulation factors, anticoagulants and other substances on their surface. The properties of platelets interacting with the components of the vessel walls make it possible to form a temporary clot and stop bleeding in small vessels (platelet-vascular hemostasis). A temporary increase in platelet count can be observed after intense physical activity. A slight physiological decrease in platelet levels is observed in women during menstruation. A moderate decrease in platelet count can sometimes be observed in apparently healthy pregnant women.

Clinical signs of a decrease in platelet count - thrombocytopenia (increased tendency to intradermal hemorrhage, bleeding gums, menorrhagia, etc.) - usually occur only when the platelet count decreases below 50x10 3 cells / μl.

A pathological decrease in the number of platelets occurs due to their insufficient formation in a number of diseases of the blood system, as well as with increased consumption or destruction of platelets (autoimmune processes). After massive bleeding followed by intravenous infusions of plasma substitutes, the platelet count may decrease to 20-25% of the original value due to dilution.

An increase in the number of platelets (thrombocytosis) can be reactive, accompanying certain pathological conditions (as a result of the production of immunomodulators that stimulate platelet formation) or primary (due to defects in the hematopoietic system).

Neutrophils

They make up 50-75% of all leukocytes. In peripheral blood, two morphological types of these cells are normally found: band (younger) and segmented (mature) neutrophils. Less mature cells of the granulocytic series - young (metamyelocytes), myelocytes, promyelocytes - are normally found in the bone marrow and appear in the peripheral blood only in case of pathology. The appearance of the latter in the peripheral bloodstream indicates either stimulation of granulocyte formation in the bone marrow (reactive changes) or the presence of hemoblastosis. Mature neutrophils circulate in the blood for 8-10 hours, then enter the tissues. The lifespan of a neutrophil granulocyte in tissues is 2-3 days. The number of neutrophils, if necessary, can quickly increase due to the mobilization of mature cells from the parietal pool of the vascular bed or bone marrow reserve, or due to increased hematopoiesis. The main function of neutrophils is to participate in the fight against microorganisms through their phagocytosis. The contents of the granules are capable of destroying almost any microbes. Neutrophils contain numerous enzymes that cause bacteriolysis and digestion of microorganisms.

Options for changing (shifting) the leukocyte formula.

Neutrophilia (an increase in the number of neutrophils) can be reactive (associated with infection, inflammation, tumor or endocrine disorders) or associated with primary disorders of hematopoiesis (hemoblastoma).

Neutropenia (a decrease in the absolute neutrophil count to less than 1800/μl) can be caused by depletion of the neutrophil reserve (for example, due to septicemia), autoimmune diseases (agranulocytosis, sometimes caused by drugs), diseases of the blood system and other pathological conditions.

“Shift to the left”: (“rejuvenation” of neutrophils): an increased number of band neutrophils is present in the blood, the appearance of metamyelocytes (young) and myelocytes is possible.

Eosinophils

Eosinophils make up 0.5-5% of all blood leukocytes; they are in circulation for about 30 minutes, after which they enter the tissues, where they remain for about 12 days. Changes in the content of eosinophils in peripheral blood are the result of a balance in the production of cells in the bone marrow, their migration into tissues and destruction.

Assessing the dynamics of changes in the number of eosinophils during the inflammatory process has a certain prognostic value.

Eosinopenia (a decrease in the number of eosinophils in the blood less than 0.2x10 "/l) is often observed at the beginning of inflammation. An increase in the number of eosinophils (> 5%) accompanies the beginning of recovery. However, a number of infectious and other diseases with high levels of IgE are characterized by eosinophilia even after the end of the inflammatory process, which indicates an incomplete immune response.At the same time, a decrease in the number of eosinophils in the active phase of the disease often indicates the severity of the process and is an unfavorable sign.

Basophils

The smallest population of leukocytes. Basophils account for an average of only 0.5% of the total number of blood leukocytes. Ripe baeophils enter the bloodstream, where they circulate for about 6 hours. Then they migrate into tissues, where they die 1-2 days after performing their function. These are cells related to tissue mast cells. Basophils are capable of phagocytosis. Their granules contain sulfated or carboxylated acidic proteins, such as heparin, which acquire a blue color when stained with Giemsa, and other biologically active substances.

Basophils participate in allergic reactions involving IgE-dependent mechanisms and initiate the development of an immediate-type anaphylactic hypersensitivity reaction.

Basophilia (basophil content >0.15x10"/l) can be associated with allergic reactions, viral diseases, chronic infections, inflammatory processes, and cancer.

Lymphocytes

Lymphocytes have the ability to synthesize and secrete into the blood various protein regulators - cytokines, through which they coordinate and regulate the immune response. An increase in the content of lymphocytes is observed as a reaction to acute viral infections, chronic infections (tuberculosis and syphilis), this may also be a consequence of specific hematological diseases.

It should be borne in mind that the leukocyte formula reflects the relative (percentage) content of different types of leukocytes, and an increase or decrease in the percentage of lymphocytes can be both absolute and relative. Thus, a high percentage of lymphocytes in the formula may be a consequence of true (absolute) lymphocytosis, when the content of blood lymphocytes exceeds 3000/μl, or a decrease in the absolute number of leukocytes of other types (usually neutrophils) - in this case, lymphocytosis is relative. Lymphopenia (decrease in the number of lymphocytes) can also be absolute, when the number of cells falls below 1000/μl, or relative - be a consequence of an increase in the number of granulocytes.

Monocytes

Monocytes are the largest cells among leukocytes, make up 2-10% of all leukocytes, and belong to agranulocytes. In peripheral blood, monocytes amount to 80-600x10"/l. Monocytes circulate in the blood from 36 to 104 hours, then leave the vascular bed. In tissues, monocytes differentiate into organ- and tissue-specific macrophages. The lifespan of tissue macrophages (histiocytes) is calculated in months and years. Macrophages participate in the formation and regulation of the immune response, performing the function of presenting antigen to lymphocytes and being a source of biologically active substances (including regulatory cytokines, interleukins, interferons, complement components).

Monocytes/macrophages capable of amoeboid movement exhibit pronounced phagocytic and bactericidal activity. One macrophage is capable of absorbing up to 100 microorganisms, while a neutrophil is only 20-30. They appear at the site of inflammation after neutrophils and show maximum activity in an acidic environment, in which neutrophils lose their activity. At the site of inflammation, macrophages phagocytize microorganisms, as well as dead leukocytes and damaged cells of inflamed tissue, cleaning the site of inflammation and preparing it for regeneration. Macrophages are more effective than neutrophils in phagocytosis of mycobacteria, fungi and macromolecules. In the spleen, macrophages ensure the disposal of sensitized and aging red blood cells. Monocytosis (an increase in the absolute number of monocytes by more than 10xNU/l) is observed in patients with chronic infections or inflammatory processes.

ESR (Erythrocyte Sedimentation Rate, ESR)

Nonspecific indicator of inflammation.

ESR is an indicator of the rate of separation of blood stabilized by an anticoagulant in a capillary into two layers: the upper (transparent blood plasma) and the lower (settled red blood cells and other blood cells). ESR is estimated by the height of the formed layer of blood plasma (in mm) in 1 hour. The specific gravity of erythrocytes is higher than the specific gravity of plasma, therefore, under the influence of gravity, erythrocytes settle to the bottom. The process of sedimentation (sedimentation) of erythrocytes can be divided into 3 phases, which occur at different rates. At first, red blood cells slowly settle into individual cells. Then they form aggregates - “coin columns”, and subsidence occurs faster. In the third phase, a lot of red blood cell aggregates are formed, their sedimentation first slows down and then gradually stops. The main factor influencing the formation of “coin columns” and the erythrocyte sedimentation rate is the protein composition of the blood plasma. Proteins of the acute phase of inflammation, adsorbed on the surface of erythrocytes, reduce their charge and repulsion from each other, contribute to the formation of “coin columns” and accelerated sedimentation of erythrocytes. An increase in the content of acute-phase proteins, for example, C-reactive protein, haptoglobin, alpha-1-antitrypsin, during acute inflammation leads to an increase in ESR. In acute inflammatory and infectious processes, a change in the erythrocyte sedimentation rate is observed 24 hours after an increase in temperature and an increase in the number of leukocytes. In chronic inflammation, an increase in ESR is caused by an increase in the concentration of fibrinogen and immunoglobulins. A decrease in the content of erythrocytes in the blood (anemia) leads to an acceleration of ESR, and, on the contrary, an increase in the content of erythrocytes in the blood slows down the rate of their sedimentation. Determination of ESR is used in screening examinations, as well as in monitoring the course and monitoring the effectiveness of treatment of inflammatory and infectious diseases, usually in combination with a general blood test.

The ESR level varies depending on many physiological factors. ESR values ​​in women are slightly higher than in men. Changes in the protein composition of the blood during pregnancy lead to an increase in ESR. The values ​​may fluctuate during the day; the maximum level is observed during the daytime.

To determine an accurate diagnosis and evaluate the effectiveness of treatment, the doctor usually prescribes a blood test, which examines the leukocyte formula. Let's figure out what this concept means, what indicators are considered normal, and what these or other deviations may indicate?

Functions of leukocytes

So, what is the leukocyte formula, and how can it be determined? The leukocyte formula of blood shows the percentage of different types of leukocytes in human blood plasma. Each of the existing types of cells reacts in a certain way to the penetration of viruses or pathogenic bacteria into the body and the development of diseases. Therefore, decoding the leukocyte formula, showing the composition of the blood, allows the doctor to diagnose the type of disease, judge its severity, and monitor the progress of treatment of the disease.

The leukocyte blood formula considers the composition of two main groups of leukocytes in the blood:

• Granulocytes, which in turn are divided into:
  • Eosinophils.
  • Basophils.
  • Neutrophils.
• Agranulocytes, which include:
  • Monocytes.
  • Lymphocytes of various types.

Granulocytes have a large granular structure with a nucleus divided into segments.

Their varieties are divided according to their ability to be painted with certain types of dyes.

Eosinophils, when tested in a laboratory, are able to absorb the acidic dye eosin, which is the reason for their name. Basophils are stained with alkaline dyes. Neutrophils are able to perceive both alkaline and acidic compounds.

A doctor may prescribe a clinical blood test with a leukocyte formula in the following cases:

• to determine the cause of the disease,
• to identify the severity of the disease, the presence of complications,
• to monitor the course of the disease and evaluate the effectiveness of treatment,
• to assess further forecasts,
• when conducting preventive examinations or planning pregnancy to identify existing pathologies.

In order to ensure that the transcript does not contain distorted indicators when analyzing the leukocyte formula of blood, you should properly prepare for the study. To do this, you need to follow these recommendations:

• 24 hours before the test, do not drink alcohol-containing drinks or medications,
• donate blood for analysis on an empty stomach, no earlier than 6-8 hours after eating,
• do not smoke for at least 30 minutes before collecting a sample for testing,
• Avoid strong physical or emotional stress 30-40 minutes before blood collection.

To determine the leukocyte formula, venous or capillary blood is taken. It is treated with special reagents that stain the cells in one color or another, which makes it possible to count their number.

Cell counting is carried out by a laboratory assistant using a microscope or an automatic analyzer.

A modern leukocyte count counter significantly increases the reliability of the results obtained, since it makes it possible to analyze more than 2 thousand cells. In comparison, microscopic examination can evaluate the types of approximately 200 cells.

The following factors can affect the reliability of the result:

• gender and age, race of the patient,
• use of medicines,
• pregnancy.

For this reason, the results obtained should be interpreted taking into account the individual characteristics of the patient. If there are deviations from the norm in the leukocyte formula, a repeat analysis should be done. Sometimes incorrect calculation of the leukocyte formula is caused by errors in blood sampling, improper preparation of the smear, the quality of the reagents and other factors.

Norms

Only a qualified specialist can correctly decipher the leukocyte formula of blood. Because to make a diagnosis, you should pay attention not only to the relative content of leukocytes, but also to their absolute values, as well as the levels of other blood parameters.

For adults, the following leukocyte standards are accepted:

Deviations

A shift in the leukocyte formula is a change in the ratios of different types of these cells in the blood. There are shifts to the left or to the right.

Shift left

It is curious that the overwhelming majority of all leukocytes are represented by mature neutrophils. Their number, as already mentioned, reaches 70-72%. But young neutrophils with a rod-shaped nucleus make up no more than 5% of the total number of leukocytes.

The reason for this is that immature cells are in the blood for a very short period of time, since they mature quite quickly and turn into mature neutrophils with a segmented nucleus.

Segmented particles are the main fighters against infections and viruses. Therefore, when the body is attacked by any pathogens, a command is sent to the bone marrow to produce new cells. In other words, the disease is a stimulus for the intensive reproduction of new (young) neutrophils. Accordingly, a sharp change in their number above the normative 5% may be a sign of the following pathologies:

• acute diseases – pyelonephritis, prostatitis,
• necrosis, purulent infections,
• acidosis,
• severe bleeding
• severe intoxication,
• leukemia,
• malignant neoplasms,
• significant physical activity.

Shift right

In the case when a blood test shows the presence of exclusively mature neutrophils. In this case, young cells with a rod-shaped nucleus are reduced or absent altogether. In this situation, we are talking about shifting the formula to the right. Such insufficient reproduction of new blood cells is typical for the following pathologies:

• liver and kidney diseases,
• radiation sickness,
• megaloblastic anemia,
• conditions after blood transfusion,
• vitamin B12 deficiency or folic acid deficiency.

The degree of formula shift determines the leukocyte index, which reflects the ratio of jointly counted young and juvenile neutrophils to the number of mature cells with a segmented nucleus. Acceptable standards for such an index are in the range of 0.05-0.1.

In addition to neutrophils, deviations from the norm in the analysis can also be observed for other leukocytes.

The cause of an increased number of lymphocytes may be:

• Infectious mononucleosis,
• various viral infections, for example, rubella, chickenpox, hepatitis,
• severe bacterial diseases such as tuberculosis, brucellosis, toxoplasmosis, syphilis, whooping cough,
• chronic lymphocytic leukemia, lymphosarcoma, in which the number of lymphocytes can reach 50-100 Gg/l,
• hyperthyroidism,
• some types of anemia.

A decrease in the level of lymphocytes is typical for:

• lymphogranulomatosis,
• renal failure,
• autoimmune diseases,
• acute infections,
• radiation sickness,
• taking corticosteroid drugs.

An increase in the number of eosinophils above the normative values ​​is relatively rare. Typically this situation occurs when:

A decrease in the level of these cells is typical for:

• conditions after severe stress,
• taking adenocorticotropic hormonal drugs,
• Cushing's syndrome.

ESR

Often, for diagnosis, the doctor prescribes a general blood test with leukocyte count and ESR. This CBC is often used as a screening test for:

• infectious diseases,
• rheumatological diseases,
• renal pathology,
• the presence of malignant neoplasms.

The principle of this study is that the red blood cell has a density slightly greater than the density of blood plasma. Because of this, such cells settle at a certain speed to the bottom of the test tube with a blood sample that is deprived of the ability to clot.

Under the influence of various processes, for example, with the appearance of tumor cells or infection, lymphocytes begin to intensively produce certain protein compounds. Under their influence, the aggregation of erythrocytes (sticking together) increases, which leads to an increase in their density and accelerates the settling of particles to the bottom of the test tube.

The normal level of ESR for men is 1-10 mm/hour; for women it is slightly higher and ranges from 2-15 mm/hour.

The erythrocyte sedimentation rate increases significantly in the case of inflammatory processes, infectious and autoimmune diseases, in the presence of anemia, tumors, rheumatism and other pathologies. The results of the analysis must be interpreted by a qualified specialist, taking into account the presence of clinical symptoms and data from other examinations.

Studying the ratio of leukocytes in the blood is a very important element in diagnosing diseases and monitoring the effectiveness of treatment. The leukocyte balance determined during the study will allow the doctor to promptly identify hidden pathologies, assess the prognosis of the disease and prescribe the correct therapy.

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Clinical blood test

Clinical blood test (HOW) (complete blood count, complete blood count (CBC)) - a medical or nursing analysis that allows you to evaluate the hemoglobin content in the red blood system, the number of red blood cells, color index, the number of leukocytes, platelets. A clinical blood test allows you to examine the leukogram and erythrocyte sedimentation rate (ESR).

Using this analysis, it is possible to identify anemia (decrease in hemoglobin - leukocyte formula), inflammatory processes (leukocytes, leukocyte formula), etc.

Blood counts

Currently, most indicators are performed on automatic hematology analyzers, which are able to simultaneously determine from 5 to 24 parameters. Of these, the main ones are the number of leukocytes, hemoglobin concentration, hematocrit, the number of red blood cells, the average volume of an erythrocyte, the average concentration of hemoglobin in an erythrocyte, the average hemoglobin content in an erythrocyte, the half-width of the size distribution of erythrocytes, the number of platelets, the average volume of a platelet.

• WBC(white blood cells - white blood cells) - absolute content of leukocytes (norm 4-9 10 9 (\displaystyle 10^(9)) cells/l) - formed elements of blood - responsible for recognizing and neutralizing foreign components, the body's immune defense against viruses and bacteria, elimination of dying cells of one’s own body.
• R.B.C.(red blood cells - red blood cells) - absolute content of erythrocytes (normal 4.3-5.5 cells/l) - formed elements of blood - containing hemoglobin, transporting oxygen and carbon dioxide.
• HGB(Hb, hemoglobin) - hemoglobin concentration in whole blood (normal 120-140 g/l). For analysis, a cyanide complex or cyanide-free reagents are used (as a replacement for toxic cyanide). It is measured in moles or grams per liter or deciliter.
• HCT(hematocrit) - hematocrit (norm 0.39-0.49), part (% = l/l) of the total blood volume attributable to blood cells. Blood consists of 40-45% formed elements (erythrocytes, platelets, leukocytes) and 60-55% plasma. Hematocrit is the ratio of the volume of formed elements to blood plasma. It is believed that hematocrit reflects the ratio of the volume of red blood cells to the volume of blood plasma, since red blood cells mainly make up the volume of blood cells. Hematocrit depends on the number of RBCs and the MCV value and corresponds to the product RBC*MCV.
• PLT(platelets - blood platelets) - the absolute content of platelets (the norm is 150-400 10 9 (\displaystyle 10^(9)) cells/l) - the formed elements of blood - involved in hemostasis.

Red blood cell indices (MCV, MCH, MCHC):

• MCV- the average volume of an erythrocyte in cubic micrometers (µm) or femtoliters (fl) (the norm is 80-95 fl). Old tests indicated: microcytosis, normocytosis, macrocytosis.
• MCH- the average hemoglobin content in an individual erythrocyte in absolute units (norm 27-31 pg), proportional to the ratio “hemoglobin/number of erythrocytes”. Color indicator of blood in old tests. CPU=MCH*0.03
• MCHC- the average concentration of hemoglobin in the erythrocyte mass, and not in whole blood (see above HGB) (the norm is 300-380 g/l, reflects the degree of saturation of the erythrocyte with hemoglobin. A decrease in MCHC is observed in diseases with impaired hemoglobin synthesis. However, this is the most stable hematological indicator. Any inaccuracy associated with the determination of hemoglobin, hematocrit, MCV leads to an increase in MCHC, therefore this parameter is used as an indicator of instrument error or error made when preparing the sample for research.

Platelet indices (MPV, PDW, PCT):

• MPV(mean platelet volume) - average platelet volume (normal 7-10 fl).
• PDW- relative width of platelet distribution by volume, an indicator of platelet heterogeneity.
• PCT(platelet crit) - thrombocrit (norm 0.108-0.282), the proportion (%) of the volume of whole blood occupied by platelets.

Leukocyte indices:

• LYM% (LY%)(lymphocyte) - relative (%) content (normal 25-40%) of lymphocytes.
• LYM# (LY#)(lymphocyte) - absolute content (norm 1.2-3.0 x 10 9 (\displaystyle 10^(9)) / l (or 1.2-3.0 x 10 3 (\displaystyle 10^(3)) / µl)) lymphocytes.
• MXD% (MID%)- relative (%) content of the mixture (norm 5-10%) of monocytes, basophils and eosinophils.
• MXD# (MID#)- absolute content of the mixture (norm 0.2-0.8 x 10 9 (\displaystyle 10^(9)) / l) of monocytes, basophils and eosinophils.
• NEUT% (NE%)(neutrophils) - relative (%) content of neutrophils.
• NEUT# (NE#)(neutrophils) - absolute content of neutrophils.
• MON% (MO%)(monocyte) - relative (%) content of monocytes (normal 4-11%).
• MON# (MO#)(monocyte) - absolute content of monocytes (norm 0.1-0.6 10 9 (\displaystyle 10^(9)) cells/l).
• EO%- relative (%) content of eosinophils.
• EO#- absolute content of eosinophils.
• BA%- relative (%) content of basophils.
• BA#- absolute content of basophils.
• IMM%- relative (%) content of immature granulocytes.
• IMM#- absolute content of immature granulocytes.
• ATL%- relative (%) content of atypical lymphocytes.
• ATL#- absolute content of atypical lymphocytes.
• GR% (GRAN%)- relative (%) content (normal 47-72%) of granulocytes.
• GR# (GRAN#)- absolute content (norm 1.2-6.8 x 10 9 (\displaystyle 10^(9)) / l (or 1.2-6.8 x 10 3 (\displaystyle 10^(3)) / µl) ) granulocytes.

Erythrocyte indices:

• HCT/RBC- average volume of red blood cells.
• HGB/RBC- average hemoglobin content in an erythrocyte.
• HGB/HCT- the average concentration of hemoglobin in the erythrocyte.
• RDW- Red cell Distribution Width - “width of distribution of erythrocytes”, the so-called “anisocytosis of erythrocytes” - an indicator of the heterogeneity of erythrocytes, calculated as the coefficient of variation of the average volume of erythrocytes.
• RDW-SD- relative width of the distribution of erythrocytes by volume, standard deviation.
• RDW-CV- relative width of distribution of erythrocytes by volume, coefficient of variation.
• P-LCR- coefficient of large platelets.
• ESR (ESR) (erythrocyte sedimentation rate) is a nonspecific indicator of the pathological condition of the body.

As a rule, automatic hematology analyzers also build histograms for red blood cells, platelets and white blood cells.

Hemoglobin

Hemoglobin(Hb, Hgb) in a blood test is the main component of red blood cells that transports oxygen to organs and tissues. For analysis, a cyanide complex or cyanide-free reagents are used (as a replacement for toxic cyanide). It is measured in moles or grams per liter or deciliter. Its definition has not only diagnostic, but also prognostic significance, since pathological conditions leading to a decrease in hemoglobin content lead to oxygen starvation of tissues.

• men - 135-160 g/l (gigamoles per liter);
• women - 120-140 g/l.

An increase in hemoglobin is observed when:

• primary and secondary erythremia;
• dehydration (false effect due to hemoconcentration);
• excessive smoking (formation of functionally inactive HbCO).

A decrease in hemoglobin is detected when:

• anemia;
• overhydration (a false effect due to hemodilution - “dilution” of the blood, increasing the volume of plasma relative to the volume of the totality of formed elements).

Red blood cells

Red blood cells(E) in a blood test - red blood cells, which are involved in the transport of oxygen to tissues and support biological oxidation processes in the body.

• men - (4.0-5.15) x 10 12 (\displaystyle 10^(12))/l
• women - (3.7-4.7) x 10 12 (\displaystyle 10^(12))/l
• children - (3.80-4.90) x 10 12 (\displaystyle 10^(12))/l

An increase (erythrocytosis) in the number of red blood cells occurs when:

• neoplasms;
• hydrocele of the renal pelvis;
• the influence of corticosteroids;
• Cushing's disease and syndrome;
• Polycythemia vera disease;
• treatment with steroids.

A slight relative increase in the number of red blood cells may be associated with blood thickening due to a burn, diarrhea, or taking diuretics.

A decrease in the content of red blood cells in the blood is observed when:

• blood loss;
• anemia;
• pregnancy;
• hydremia (intravenous administration of large amounts of fluid, that is, infusion therapy)
• with the outflow of tissue fluid into the bloodstream while reducing edema (therapy with diuretics).
• reducing the intensity of red blood cell formation in the bone marrow;
• accelerated destruction of red blood cells;

Leukocytes

Leukocytes(L) - blood cells formed in the bone marrow and lymph nodes. There are 5 types of leukocytes: granulocytes (neutrophils, eosinophils, basophils), monocytes and lymphocytes. The main function of leukocytes is to protect the body from foreign antigens (including microorganisms, tumor cells; the effect also manifests itself in the direction of transplant cells).

An increase (leukocytosis) occurs when:

• acute inflammatory processes;
• purulent processes, sepsis;
• many infectious diseases of viral, bacterial, fungal and other etiologies;
• malignant neoplasms;
• tissue injuries;
• myocardial infarction;
• during pregnancy (last trimester);
• after childbirth - during the period of feeding the baby with breast milk;
• after heavy physical exertion (physiological leukocytosis).

The decrease (leukopenia) is caused by:

• aplasia, bone marrow hypoplasia;
• exposure to ionizing radiation, radiation sickness;
• typhoid fever;
• viral diseases;
• anaphylactic shock;
• Addison-Beermer disease;
• collagenoses;
• under the influence of certain medications (sulfonamides and some antibiotics, non-steroidal anti-inflammatory drugs, thyreostatics, antiepileptic drugs, antispasmodic oral drugs);
• damage to the bone marrow by chemicals, drugs;
• hypersplenism (primary, secondary);
• acute leukemia;
• myelofibrosis;
• myelodysplastic syndromes;
• plasmacytoma;
• metastases of neoplasms to the bone marrow;
• pernicious anemia;
• typhus and paratyphoid;
• collagenoses.

Leukocyte formula

Leukocyte formula (leukogram) is the percentage of different types of leukocytes, determined by counting them in a stained blood smear under a microscope.

In addition to the leukocyte indices listed above, leukocyte, or hematological, indices are also proposed, calculated as the ratio of the percentage of different types of leukocytes, for example, the index of the ratio of lymphocytes and monocytes, the index of the ratio of eosinophils and lymphocytes, etc.

Color index

Main article: Blood color index

Color Index (CPU)- degree of saturation of erythrocytes with hemoglobin:

• 0.85-1.05 is normal;
• less than 0.80 - hypochromic anemia;
• 0.80-1.05 - red blood cells are considered normochromic;
• more than 1.10 - hyperchromic anemia.

In pathological conditions, there is a parallel and approximately equal decrease in both the number of red blood cells and hemoglobin.

A decrease in CPU (0.50-0.70) occurs when:

• iron deficiency anemia;
• anemia caused by lead intoxication.

An increase in CPU (1.10 or more) occurs when:

• deficiency of vitamin B12 in the body;
• folic acid deficiency;
• cancer;
• polyposis of the stomach.

To correctly assess the color index, it is necessary to take into account not only the number of red blood cells, but also their volume.

ESR

(ESR) is a nonspecific indicator of the pathological state of the body. Fine:

• newborns - 0-2 mm/h;
• children under 6 years old - 12-17 mm/h;
• men under 60 years old - up to 8 mm/h;
• women under 60 years old - up to 12 mm/h;
• men over 60 years old - up to 15 mm/h;
• women over 60 years old - up to 20 mm/h.

An increase in ESR occurs when:

• infectious and inflammatory disease;
• collagenosis;
• damage to the kidneys, liver, endocrine disorders;
• pregnancy, postpartum period, menstruation;
• bone fractures;
• surgical interventions;
• anemia;
• oncological diseases.

It can also increase during physiological conditions such as food intake (up to 25 mm/h), pregnancy (up to 45 mm/h).

A decrease in ESR occurs when:

• hyperbilirubinemia;
• increased levels of bile acids;
• chronic circulatory failure;
• erythremia;
• hypofibrinogenemia.

Comparison of the results of general analysis of capillary and venous blood

Venous blood tests are the recognized “gold standard” of laboratory diagnostics for many indicators. However, capillary blood is a frequently used type of biomaterial for performing a general blood test. In this regard, the question arises about the equivalence of the results obtained from the study of capillary (C) and venous (V) blood.

A comparative assessment of 25 indicators of a general blood test for different types of biomaterial is presented in the table as the average analysis value:

All 25 parameters studied are divided into 3 groups: (1) statistically significantly decreasing in capillary blood relative to venous blood, (2) significantly increasing, and (3) not changing:

1) There are eleven indicators in this group, 4 of which are within -5% (HCT, MCV, LY%, RDW-SD) - their CIs are within the bias boundaries of -5% and 0%, but do not cross them. CIs for WBC, LY, NE and PCT were not included within the -5% bias limits. The PLT (-19.64%), BA (-37.09%) and BA% (-31.77%) indicators decrease the most.

2) There are 7 indicators in this group. For MO%, P-LCR, PDW and MPV, the bias is more than 5%, but the 95% CI of MPV includes a bias value of 5%. The deviations of the remaining 3 indicators of this group (MCH, MCHC, RDW-CV) are less than 5%.

3) There are 7 indicators in this group: RBC, HGB, MO, NE%, EO, EO%, ESR. No statistically significant differences were found for them.

When comparing the results of capillary and venous blood, it is necessary to take into account a significant decrease in the number of basophils and platelets in capillary blood (leading to an increase in the coefficient of large platelets, distribution of platelets by volume, average platelet volume and a significant decrease in thrombocrit), as well as a less significant decrease in the number of leukocytes, lymphocytes and neutrophils, which causes a slight increase in the relative number of monocytes.

Indicators of the third group (RBC, HGB, MO, NE%, EO, EO%, ESR), along with blood parameters of the first and second groups, whose 95% CI included no more than 5% deviation (HCT, MCV, LY%, RDW -SD, MCH, MCHC, RDW-CV), can be determined in capillary blood with strict adherence to preanalytical rules without any compromise in the accuracy of clinical assessment.

General blood test norms

General blood test norms for children under 1 year of age

General blood test norms for children aged 1 to 12 years

Hemoglobin

Red blood cell count

Total white blood cell count

Hematocrit

MCH, MCHC, MCV, color index (CPU)- norm

Color Index (CPU)- This is a classic method for determining the hemoglobin concentration in red blood cells. Currently, it is gradually being replaced by the MCH index in blood tests. These indices reflect the same thing, only expressed in different units.

Leukocyte formula

Types of leukocytes, normal

Neutrophils