Leukocyte formula: concept, norm in children and adults, interpretation, deviations and shifts. Deciphering the leukocyte formula in a clinical blood test What is called the leukocyte formula

Blood indicators characterize the state of human health and can greatly facilitate diagnosis. By determining the leukocyte formula, one can assume the type of disease, judge its course, the presence of complications, and even predict its outcome. And to understand the changes taking place in the body will help deciphering the leukogram.

What does the leukocyte blood formula show?

Leukocyte formula blood is the ratio of different types of leukocytes, usually expressed as a percentage. The study is carried out within the framework of general analysis blood.

White blood cells are called blood cells which represent the body's immune system. Their main functions are:

• protection against microorganisms that can cause health problems;
• participation in the processes that occur in the body under the influence of various pathogenic factors and cause disturbances in normal life (various diseases, exposure to harmful substances, stress).

The following types of leukocytes are distinguished:

Deciphering the indicators of LYM (lymphocytes) in a blood test:

Plasma cells (plasmocytes) are involved in the formation of antibodies and are normally present in a very low amount only in the blood of children, in adults they are absent and can appear only in case of pathologies.

A study of the qualitative and quantitative characteristics of leukocytes can help in making a diagnosis, since with any changes in the body, the percentage of some types of blood cells increases or decreases due to an increase or decrease in varying degrees of others.

The doctor prescribes this analysis in order to:

• get an idea of ​​the severity of the patient's condition, judge the course of the disease or pathological process, learn about the presence of complications;
• establish the cause of the disease;
• evaluate the effectiveness of the prescribed treatment;
• predict the outcome of the disease;
• in some cases, assess the clinical diagnosis.

Technique, calculation and interpretation of the analysis

To calculate the leukocyte formula with a blood smear, certain manipulations are performed, dried, treated with special dyes and examined under a microscope. The laboratory assistant notes those blood cells that fall into his field of vision, and does this until a total of 100 (sometimes 200) cells are accumulated.

The distribution of leukocytes over the surface of the smear is uneven: the heavier ones (eosinophils, basophils and monocytes) are located closer to the edges, and the lighter ones (lymphocytes) are closer to the center.

There are 2 ways to calculate:

• Schilling method. It consists in determining the number of leukocytes in four areas of the smear.
• Filipchenko method. In this case, the smear is mentally divided into 3 parts and counted along a straight transverse line from one edge to the other.

On a sheet of paper in the appropriate columns, the quantity is noted. After that, each type of leukocyte is counted - how many of which cells were found.

It should be borne in mind that counting cells in a blood smear when determining the leukocyte formula is a very inaccurate method, since there are many hard-to-remove factors that introduce errors: errors in blood sampling, smear preparation and staining, human subjectivity in interpreting cells. A feature of some types of cells (monocytes, basophils, eosinophils) is that they are unevenly distributed in the smear.

If necessary, the calculation of leukocyte indices is performed, which is the ratio of those contained in the patient's blood various forms leukocytes, also sometimes the ESR indicator (erythrocyte sedimentation rate) is used in the formula.

The norms of the leukocyte formula depend on the age of the person. In women, the difference also lies in the fact that the indicators can change during the period of ovulation, after or during menstruation, during pregnancy, after childbirth. That is why in cases of deviations, a gynecologist should be consulted.

Possible deviations from the norm in the leukogram

An increase or decrease in the level of certain types of leukocytes indicates pathological changes occurring in the body.

Causes of changes in the number of leukocytes in the blood - table

Shift of the leukocyte formula

In medicine, there are concepts of a shift in the leukocyte formula, indicating deviations in the health status of patients.

Shift of the leukocyte formula to the left and right - table

To obtain data on the patient's condition, based on the results of the leukocyte formula, the shift index is taken into account. It is determined by the formula: IP \u003d M (myelocytes) + MM (metamyelocytes) + P (stab neutrophils) / C (segmented neutrophils). The norm of the shift index of the leukocyte formula in an adult is 0.06.

In some cases, there may be such a phenomenon as a significant content of young cells in the blood - metamyelocytes, myelocytes, promyelocytes, myeloblasts, erythroblasts. This usually indicates diseases of a tumor nature, oncology and metastasis (the formation of secondary tumor foci).

Crossover of the leukocyte formula

The cross of the leukocyte formula is a concept that arises when analyzing the blood of a child. If in an adult, changes in the blood are caused by diseases or a significant impact on the body of harmful factors, then in young children, changes occur due to the formation immune system. This phenomenon is not a pathology, but is considered absolutely normal. The non-standard numbers are due only to the formation of immunity.

The first crossover of the leukocyte formula usually occurs towards the end of the first week of a baby's life. At this time, the number of neutrophils and lymphocytes in the blood is equalized (they become approximately 45% each), after which the number of lymphocytes continues to grow, and neutrophils decrease. This is considered a normal physiological process.

The second crossover of the leukocyte formula occurs at the age of 5–6 years, and only by the age of ten, blood counts approach the norm of an adult.

How to determine the nature of the inflammatory process by a blood test - video

The leukocyte formula is able to give many answers in case of difficulties in diagnosing the disease and prescribing therapy, as well as characterize the patient's condition. However, it is better to entrust the interpretation of a blood test to an experienced specialist. The doctor can give detailed explanations and adjust the treatment.

The level of leukocytes is one of the main indicators of the general blood test. However, there are several types of leukocytes. Their differentiated count allows you to get more complete information about the patient's condition. This type of study is called the calculation of the leukocyte formula, or leukogram, and is part of a number of comprehensive laboratory examination programs.

An analysis of the leukocyte formula is prescribed during routine preventive examinations, before hospitalization, for the diagnosis of infectious, inflammatory and hematological diseases, as well as for monitoring the course of the disease or the effectiveness of the prescribed therapy.

Leukocyte formula and its role in diagnosis

So, the leukocyte formula includes indicators of the total concentration of leukocytes and the percentage of their main types. For the study, automatic hematological analyzers are used. They are able to isolate 5 types of leukocytes - these are neutrophils, lymphocytes, monocytes, eosinophils and basophils. If abnormal cells (atypical structure) are found among the leukocytes, the analyzer issues a warning about the need to view the stained blood sample under a microscope. In the case when microscopy revealed abnormal cells, they are additionally reflected in the analysis form for the leukocyte formula.

Below are the reference values ​​for the concentration of all types of leukocytes:

If the number of leukocytes in the blood test deviates from the norm in one direction or another, it is important to know which subpopulations of them have gone beyond the reference values. This will greatly facilitate the diagnosis. However, it should be borne in mind that shifts in the leukocyte formula are not specific and do not serve as an unambiguous sign of a particular disease.

Neutrophils are the most numerous category of leukocytes. They are the first to fight the infection. Mature forms of neutrophils are called segmented due to the division of the nucleus into segments, immature forms are called stab. These two subtypes are indicated separately in the leukocyte formula. Entering the focus of infection, neutrophils surround the bacteria and destroy them by phagocytosis. The reference values ​​of neutrophils in the leukocyte formula are as follows:

Lymphocytes there are two types (in the leukocyte formula, these two types are not differentiated). B-lymphocytes produce antibodies that "mark" the surface of foreign cells: viruses, bacteria, fungi, protozoa. After that, the body knows its enemy “by sight”. Neutrophils and monocytes read this information and kill strangers. T-lymphocytes destroy infected cells, thereby preventing the spread of infection. They are capable of recognizing and destroying cancer cells. In terms of reference values, they are as follows:

Monocytes are not presented especially massively, but they perform an important function. After spending 20–40 hours in the bloodstream, they pass into the tissues, where they become the building material for macrophages. Macrophages are able to destroy hostile cells and "keep" foreign proteins on their surface, to which lymphocytes react. Reference values ​​of monocytes:

Basophils circulate in the blood for a short time, trying to move to the tissues, where they are converted into the so-called mast cells. Basophils are activated during allergies: histamine is produced from them, and the patient feels itching and burning. In blood healthy person of any age they contain less than 1%.

It is interesting!
The leukocyte formula strongly depends on age; in childhood, it “experiences” two periods of the so-called cross - at the age of 4–5 days of life and at 4–5 years. This is due to the development of immunity in children, when the number of neutrophils and lymphocytes becomes the same - approximately 40–45% each.

In addition to the leukocyte formula, leukocyte indices can be calculated - the ratio of the concentrations of certain types of leukocytes or leukocytes with other cells. For example, the Harkavy index is calculated as the ratio of the concentration of lymphocytes to segmented neutrophils, and the hematological index of intoxication (GPI) is determined by the number of leukocytes, ESR, erythrocytes and platelets.

The procedure for donating blood for analysis of the leukocyte formula

You have to donate blood for the leukocyte formula:

Both venous and capillary blood can be taken for research. The day before blood donation, it is necessary to stop drinking alcohol, reduce physical and emotional stress, stop smoking half an hour before. Just before entering the treatment room, it is recommended to sit quietly for 10-15 minutes.

Leukocyte blood formula: decoding the results

Before constructing a leukogram, the total concentration of leukocytes in the blood is determined and a conclusion is made about the compliance of the result with the norm. Then there is a count for individual subpopulations and their percentage of the total number of leukocytes is calculated.

Keep in mind!
Enhanced level leukocytes can be triggered by overheating of the body, intense sports or hard physical work, high emotional stress, smoking, plentiful food - conditionally, this is considered the norm. When donating blood, you should follow the rules for preparing for analysis so that the results are correct.

Shift of the leukocyte formula to the left and to the right

A shift of the leukocyte formula to the left is an increase in the number of stab neutrophils and their precursors - myelocytes. This is usually a bone marrow reaction to a serious infection. Shift of the leukocyte formula to the right - an insufficient number of stab neutrophils and an increase in the number of segmented neutrophils with hypersegmented nuclei. May be one of the signs of megaloblastic anemia, diseases of the liver and kidneys.

stats increased

Indicators lowered

Leukocytes in general, they can be "reduced" due to infectious, oncological, autoimmune, endocrinological diseases. Low rate on neutrophils indicates either a massive attack on the body by bacteria or viruses, when Bone marrow does not have time to produce enough neutrophils to fight foreign cells, or hypofunction of the bone marrow in anemia or cancer. Concentration lymphocytes may decrease with acute bacterial infections, influenza, aplastic anemia, prednisolone, AIDS, systemic lupus erythematosus. Monocytes"decrease" in the treatment of prednisolone, as well as in aplastic anemia. Level reduction eosinophils in the blood may indicate an acute bacterial infection, Cushing's syndrome, Goodpasture's syndrome, and can also be observed while taking prednisolone. Basophils can be "reduced" in the acute phase of infection, with hyperthyroidism, long-term use of corticosteroids.

Wednesday, 03/28/2018

Editorial opinion

The leukocyte formula brings more clarity to the clinical picture, so you should not neglect it when ordering a general blood test. Especially if there is a suspicion of serious infections, autoimmune or oncological diseases. Thanks to modern high-performance analyzers, this examination is inexpensive and fast, and everyone can afford it.

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

Varieties 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) on hand, decoding the values ​​\u200b\u200bis useful to any person:

Separately recorded leukocyte formula. It reflects the ratio of white blood cells to each other. This is important for clinical diagnosis, as 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. They are activated by any inflammation, no matter if it is 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, young cells that do not perform any functions. A healthy person does not have them in the blood.
• stab- maturing cells that are always found in the blood. Their number increases sharply during the onset of infection.
• Segmented- the most mature, mature cells. They perform all the functions of protecting the body inherent in neutrophils. Segmented neutrophils are the latest stage in the development of myelocytes.

Lymphocytes

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

There are several types of lymphocytes:

• B-lymphocytes- create antibodies to viral and bacterial infections.
• T-lymphocytes helpers and killers- start the work of B-lymphocytes and independently destroy viral cells.
• natural killers- able to destroy cells that have been infected by the virus or that have undergone tumor changes.

Monocytes

Similar in function to neutrophils. The main work of monocytes– destroy foreign material. They perform their task with the help of phagocytosis.

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

Eosinophils and basophils

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

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

• Swelling of the face;
• Cough or runny nose;
• The skin turns red;
• A rash occurs.

Functions of leukocytes

It is not in vain that the leukoformula consists of several components. Each of these cells is important in providing the body with a healthy immune system. It all starts with the entry of a bacterium or virus into the human body. The pathogenic microbe is absorbed by the neutrophil, which digests it - phagocytosis.

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

Normal leukogram values

In each laboratory, different values ​​​​can be taken as normal, depending on the technology and the reagent used by the laboratory. Therefore, analysis in dynamic observation should be performed in one laboratory. This will keep 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 norm of the number of cells strongly depends on the sex and age of the person.

How is the analysis carried out

Blood for determining the number of leukocytes can be taken in two ways:

• capillary- from a finger.
• Venous from a peripheral vein.

Analysis indicators taken in different ways can differ even in one person. But usually these changes do not exceed normal values. Viewing blood under a microscope has always been used as a counting technique. 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 set 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 an apparatus that counts all the possible cells that it has encountered.

When using a hematology analyzer, more cells can be viewed in a short time. But in controversial cases, preference is given to viewing under a microscope by a laboratory assistant. A person can identify slight differences in appearance cells that may indicate pathology.

Why determine the leukoformula

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

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

• Assistance in making a diagnosis;
• Determining the severity or activity of the process;
• The dynamics of recovery;
• Reaction or lack thereof to drugs;
• Early detection of complications.

Change in the amount and ratio in the leukogram

When calculating the percentage of neutrophilic 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 stab 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 speaks for an active immune response. In some cases, the appearance of the most immature cells in the peripheral blood may indicate an oncological disease.

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

In cases of dispute or during clinical research the determination of the leukocyte index of intoxication (LII) can be used. This is the ratio of immature forms of neutrophils that appear when 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 an increase or decrease in leukocytes

An increase in the number of neutrophils occurs when:

• bacterial infections- angina, pyelonephritis, pneumonia;
• Intoxications 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;
• The effect of toxins on the bone marrow;
• Radiation sickness;
• Autoimmune diseases.

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

Lymphocytosis or an increased number of lymphocytes occurs when:

• Chronic bacterial infections- tuberculosis, syphilis, brucellosis;
• Acute viral diseases - influenza, chickenpox, measles;
• Tumors of the blood system- lymphomas;
• Hormonal dysfunctions- hypothyroidism;
• Macrocytic anemias- folic acid 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 the bone marrow- Irradiation, heavy metals.

Monocytes are of little or no clinical significance when considered individually. Therefore, usually their changes are evaluated in combination with other leukocyte parameters.

Monocytes usually increase with:

A decrease in the number of monocytes practically does not occur without general leukocytopenia. Therefore, it has no diagnostic value. Worth mentioning infectious mononucleosis. it 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, the detection of mononuclear cells in the blood is unacceptable.

Eosinophils and basophils are the criterion allergic reactions and some infectious diseases. Estimation of their number is also highly dependent on the total number of leukocytes in the blood test.

Low eosinophils accompany:

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

Video: Deciphering a blood test

Leukocyte blood formula is the percentage of different types leukocytes blood.

Count leukocyte formula produced in stained smears of peripheral blood, that is, taken from the finger. It is better to read the blood formula closer to the end of the smear in the thinnest place.

An increase in the number of leukocytes in the leukocyte blood count is higher normal level called leukocytosis, a decrease - leukopenia. Leukocytosis and leukopenia rarely characterized by a proportional change in the number of leukocytes of all types, for example, leukocytosis with thickening of the blood. In most cases, there is an increase or decrease in the leukocyte formula of any one type of cell. An increase or decrease in the number of certain types of leukocytes in the blood formula can be relative or absolute, depending on the total content of leukocytes - normal, high or low.

1) Evaluation of basophils: the number of basophils can only increase - basophilia.

2) Assessment of eosinophils: the number of eosinophils may increase above 5% - eosinophilia, decrease - eosinopenia or eosinophils may be absent altogether - aneosinophilia.

3) Neutrophil assessment:

a) total assessment of neutrophils: in the peripheral blood, young, stab and segmented neutrophils are normally determined. With pathology, myelocytes, promyelocytes, and even myeloblasts can enter the bloodstream. Normally, all detectable neutrophils make up 57 - 71%.

The number of neutrophils can change either upward - neutrophilia, or downward - neutropenia.

b) assessment of individual types of neutrophils: the ratio of neutrophil forms of different maturity is determined by the Schilling shift index:

M / b + P / m + M / c + Yu + P

-----------------------

Normally, the shift index is 1/16 - 1/20. If the shift index decreases, i.e. tends to zero, then this is considered a shift to the right. If the shift index increases,

those. tend to one and above - as a shift to the left. The shift to the left can be due to:

1. An increase in stab neutrophils - a simple nuclear shift to the left.

2. An increase in metamyelocytes (young) - a regenerative nuclear shift to the left.

3. The appearance of myelocytes in the blood - a hyperregenerative nuclear shift to the left.

4. Appearance of promyelocytes and (or) myeloblasts in the blood, leukemoid nuclear shift to the left.

4) Assessment of lymphocytes: an increase in the percentage of lymphocytes in peripheral blood - lymphocytosis, a decrease - lymphocytopenia.

5) Evaluation of monocytes: an increase in the percentage of monocytes in peripheral blood - monocytosis, a decrease - monocytopenia.

When evaluating the leukocyte formula, the relative (percentage) content of various kinds leukocytes, and if their change is detected, then it becomes necessary to evaluate their absolute number, which is calculated according to the proportion:

in this hemogram - 100%

X - absolute content from -% of this type of leu-

specific types of leukocytes - cocytes, indicated

in leukocyte

I. Leukocytosis.

2) Aneosinophilia.

3) Relative (93%) and absolute (31680) neutrophilia.

4) Relative lymphocytopenia (5%), no absolute lymphocytopenia (1800 in 1 µl).

5) Relative monocytopenia (2%), no absolute monocytopenia (720 in 1 µl).

1Example of a complete hemogram

Erythrocytes - 3.0 x 10 / l

Hemoglobin - 100 g/l

Reticulocytes - 1.0%

Platelets - 180 x 10 / l

Leukocytes - 18 x 10 / l

B E Y P S L M

0 14 2 7 64 10 3

On this hemogram, normochromic, regenerative anemia is determined. Lecocytosis. The content of basophils is within the normal range. Relative and absolute eosinophilia. Relative and absolute neutrophilia with a regenerative nuclear shift to the left. Relative lymphocytopenia, no absolute lymphocytopenia. Relative monocytopenia, no absolute monocytopenia.

In order to give a conclusion on the hemogram, it is necessary to determine where the changes are primary - in red or white blood, since with primary changes in red blood,

be secondary white blood disorders and vice versa.

CONCLUSION: in this case, we can talk about the primary change in white blood and suggest the presence here of a neutrophilic-eosinophilic type of leukogram, which is characteristic of infectious and infectious diseases that occur with an allergic component (for example, collagenoses - SLE, systemic scleroderma).