Decoding the results of a clinical blood test

November 14, 2018

All tests in 1 day

One type of laboratory diagnosis is a general blood test. It allows you to identify a large number of pathologies, such as malignant tumors, infectious, inflammatory diseases, etc. It can also be used to evaluate the effectiveness of patient treatment. After all, a general blood test can tell a lot about the state of the body.

Only specialized doctors can correctly decipher a general blood test. Therefore, without the appropriate medical knowledge, you should not even try to do it yourself. But it will not be superfluous to know by what indicators the blood is analyzed, as well as the norms of the test result. You will find this information in our article.

Red blood cells

Erythrocytes, or red blood cells, ensure the delivery of oxygen to all cells of the body. In English-language literature, red blood cells are called “red blood cells,” which is where the international abbreviation RBC .

To transport oxygen, these cells contain hemoglobin, which can combine with it through chemical reactions. The analyzer displays the following indicators regarding these processes:

• RBC is the number of red blood cells per liter of blood. An increase in this indicator in humans can be observed with various neoplasms, hormonal disorders, but much more often it is the result of blood thickening due to dehydration, burns, taking diuretics and some other reasons. A decrease in RBC is observed with blood loss, anemia, disorders of their formation or increased destruction. A slight decrease in the number of red blood cells during pregnancy is normal.
• HGB - total hemoglobin content. The indicator grows following an increase in RBC and decreases for the same reasons. A decrease in HGB is also observed during hemodilution—blood dilution, for example, against the background of intensive intravenous administration of a large volume of solutions. Hemoglobin levels in women are usually lower than in men due to physiological blood loss during menstruation.
• HCT - hematocrit. This is a value that reflects the ratio of all blood cells to its liquid part - plasma. Since 99% of these cells are red blood cells, the indicator is used to estimate their volume.

Red blood cell indices

In addition, the so-called erythrocyte indices are assessed:

1. MCV - average erythrocyte volume. Before the introduction of new analyzers, an accurate assessment was not carried out, and the result was designated as microcytosis, normocytosis or macrocytosis - depending on the size of the cells. An increased level of MCV may indicate a deficiency of vitamin B12, folic acid, hemolytic anemia, a decreased level may indicate iron deficiency and sideroblastic anemia.
2. MCH is the concentration of hemoglobin in one red blood cell. In older analyzers, for this purpose, the color indicator was assessed, which is 0.03 of the MCH.
3. MCHC is the average hemoglobin concentration in the erythrocyte mass, which reflects the degree of saturation of RBC with hemoglobin. It is the most stable indicator and can serve as an indicator of a correctly performed analysis.

All of the above indicators are closely related to each other and are assessed as a whole. For example, bleeding is accompanied by the loss of a large number of red blood cells. Accordingly, the total hemoglobin content also decreases, but MCH may remain normal. With a disease such as iron deficiency anemia, a slight deficiency of red blood cells occurs with a decrease in hemoglobin and various changes in erythrocyte indices. It makes no sense to list all possible changes in the body related to the content of red blood cells, and the doctor deciphers the result based on knowledge of those processes in the body in various diseases.

A separate indicator associated with red blood cells is their sedimentation rate - ESR (in modern analyzers - ESR) . This is a completely non-specific indicator, an increase in which indicates some problems in the body that the doctor needs to look for. In some cases, for example during pregnancy, an increase in ESR is physiological and is considered normal.

Leukocytes

Leukocytes are a large group of diverse cells whose task is to provide protection to the body. In international medicine, they are often referred to as WBC - white blood cells. This abbreviation denotes the total content of leukocytes in the analyzer form. The reason for the increase in WBC is various damaging factors: infections, injuries, ischemia and tissue necrosis, and others. Simply put, an increase in the number of white blood cells means that the immune system is actively involved in the fight against damage. At the same time, low values ​​of the indicator may indicate a lack of immunity under the influence of radiation, medications, certain viral infections, as well as diseases that are accompanied by impaired formation or increased destruction of leukocytes.

Leukocyte indices

In addition, in assessing the content of leukocytes, leukocyte indices , or in old forms - leukocyte formula . The general clinical analysis with the latter is called detailed. There are several types of leukocytes, which differ from each other in morphology and functional characteristics. The leukocyte formula reflects their percentage of the total number, and modern analyzers also display the absolute content of each type of these cells. They can be identified on the form by the following abbreviations:

• LYM - lymphocytes;
• MXD - agranulocytes (monocytes, basophils and eosinophils);
• NEUT—neutrophils;
• MON - monocytes;
• EO - eosinophils;
• BA - basophils.

If there is a “%” sign after the abbreviation, then we are talking about percentage, and the “#” sign means their absolute content. Changes in the leukocyte formula can serve as an indicator of a wide variety of problems in the body. Let's take a closer look at them.

The main task of neutrophils is phagocytosis - the absorption of foreign objects and their destruction. They always rush to areas of inflammation and tissue breakdown, where they perform this work, so their increased content indicates active inflammation.

In addition to neutrophils, the function of phagocytosis is performed by macrophages, into which, in the process of their development, monocytes . A high level of the latter also serves as a marker of inflammation, usually of an infectious nature.

Eosinophils take part in reactions associated with the allergic component. An increase in their number is observed in allergies, parasitic infestations, some infections and cancer.

Basophils take part in inflammation and allergies by releasing heparin, histamine and serotonin. They rarely increase in isolation, although such a phenomenon in some forms of leukemia has a serious prognostic significance.

Lymphocytes are actively involved in a wide variety of conditions, including immunodeficiencies, allergies, inflammation, and autoimmune disorders. Their high content may be a sign of childhood infections, viral hepatitis, mononucleosis, tuberculosis and a number of other diseases.

Assessment of leukocyte indices and leukocyte formula requires an understanding of the pathological and physiological processes in the body, and should not be carried out solely on the basis of tabular data. You absolutely cannot diagnose yourself based solely on the results of the analysis.

Definition and Purposes of Purpose

CBC (complete blood count) is a laboratory diagnostic method for assessing the condition of the body and searching for the source of pathology. This test can be prescribed by a doctor of any specialty. In what cases is OAC prescribed:

1. For prevention during 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 your well-being for a long time, and then a preventive test will become a reason for subsequent examination.
2. When the first symptoms of illness appear. Analysis in this case can make it possible to determine the nature of the disease, the degree of intensity of inflammation or an allergic reaction.
3. OAC may be re-prescribed to monitor the course of the disease over time. Also to assess the effectiveness of the therapy.

Platelets

The main task of platelets is to participate in stopping bleeding. They form the primary plug in the area of ​​vessel damage and participate in the formation of a blood clot. In forms, automatic analyzers are designated by the abbreviation PLT , which comes from the English word platelets (literally, “saucers”) for their peculiar shape.

A decrease in the number of platelets can be accompanied by bleeding and is a consequence of diseases and conditions such as malaria, thrombocytopenic purpura, malignant neoplasms, disseminated intravascular coagulation syndrome and some others.

A high platelet count can cause excessive blood clotting and often has no apparent cause. In this case, the condition is designated as essential thrombocythemia. In addition, thrombocytosis can be caused by iron deficiency anemia, hemolysis, some infectious and autoimmune diseases, and bone marrow damage.

This is where the work with platelets in a classic blood test ends; however, automatic analyzers even in this case offer additional diagnostic capabilities in the form of the following indicators:

• MPV —mean platelet volume. An indicator reflecting the size of cells, which directly depends on their age. An increased MPV may indicate hematological diseases, damage to the spleen, thyrotoxicosis, and progression of atherosclerosis. A decrease in the rate is observed in some genetic diseases, myocardial infarction, childhood infections, cancer chemotherapy and a number of other conditions.
• PCT is the ratio of the total volume of platelets to blood plasma (thrombocrit). It is not a specific indicator, it varies widely physiologically, but it allows one to assess the risk of bleeding and thrombosis.
• PDW —platelet distribution by volume. The indicator has no independent meaning and is assessed in conjunction with other indices.

MCV reduced

A decrease in the average volume of red blood cells most often occurs with the development of iron deficiency anemia. They can develop as a result of exposure to various factors, such as:

• Chronic blood loss.
• Lack of iron in the diet.
• Impaired absorption of iron in the intestines.

A decrease in the volume of red blood cells is observed in a variety of chronic diseases - long-term infections, oncological pathologies. Rarely, a congenital decrease in mcv is possible, for example, with thalassemia. This is a group of genetic pathologies that occur when the synthesis of hemoglobin globin chains is disrupted.

If the synthesis of the alpha chain is impaired, alpha thalassemia develops. This is a relatively mild pathology, characterized by a decrease in hemoglobin to 70-90 g/l and a decrease in the mcv index. This form of the disease often does not manifest itself in any way and is detected by chance, when studying laboratory blood parameters.

Beta thalassemia, which occurs when the synthesis of the hemoglobin beta chain is impaired, is much more severe. If defective genes were inherited from one of the parents, it is manifested by a decrease in the mcv index and hemoglobin level. When defective genes are passed on from both parents, Cooley's anemia develops. It is characterized by an extremely severe course; red blood cells not only sharply decrease in volume, but are also quickly destroyed. This leads to enlargement of the liver and spleen and disruption of their functions. To maintain life, such patients require regular blood transfusions, and a complete cure is possible with a bone marrow transplant.

Table of normal blood test values

In conclusion, we provide a table of the main normal indicators of a general blood test in adults and children. We remind you that its results can only be assessed in conjunction with examination data, other laboratory data, including biochemical blood tests and instrumental diagnostic methods. In addition, reference, that is, acceptable, values ​​depend on the type and model of diagnostic equipment. In this case, in the form of the automatic analyzer, next to the result obtained, normal values ​​​​for a specific model are reflected.