Number of leukocytes in the blood
The number of white blood cells( WBC) in circulating blood is an important diagnostic indicator. Leukocytes are formed in the red bone marrow and in the lymph nodes. The main function of leukocytes is to protect the body from foreign agents. Due to their phagocytic activity, participation in cellular and humoral immunity, exchange of histamine, antimicrobial, antitoxic, antibody-forming and other important components of immunological reactions are realized. Leukocytes include granulocyte, monocytic and lymphoid cells. Reference values of the white blood cell count are given in the table.
Table Reference values of the leukocyte count in the blood
Table Reference values of the leukocyte count in the blood
The number of leukocytes in the blood depends on the rate of inflow of cells from the red bone marrow and the rate of their release into tissues. An increase in the number of leukocytes in peripheral blood above 10x109 / l is called leukocytosis, a decrease below 4x109 / l is leukopenia. The increase or decrease in the number of individual types of leukocytes in the blood can be absolute or relative, depending on the total content of leukocytes - normal, increased or decreased. Determine the absolute content of individual types of leukocytes in a unit of blood volume by the formula: A( %) xWBC( 109 / L) / 100%, where A is the content of a specific type of white blood cells,%.For example, an increase in the percentage of lymphocytes( 60%) with a reduced total number of leukocytes( 2x109 / L) means relative lymphocytosis, since the absolute number of these cells( 1.2x109 / L) within the normal range of
. The main causes of leukocytosis are given in Table. Most often, leukocytosis develops due to acute infections, especially caused by cocci( staphylococcus, streptococcus, pneumococcus, gonococcus), E. coli, diphtheria stick, etc. In these infections, the number of leukocytes is usually 15-25109 / l. The expressed leukocytosis 20-40х109 / l is characteristic for patients with pneumococcal pneumonia, scarlet fever, severe burns. Leukocytosis develops within 1-2 hours after the onset of acute bleeding, it is especially pronounced with hemorrhage into the abdominal cavity, pleural space, joint or in the immediate vicinity of the dura mater. When interrupting tubal pregnancy, the number of leukocytes may increase to 22x109 / l, after rupture of the spleen - up to 31x109 / l. Leukocytosis usually accompanies a sharp attack of gout( up to 31x109 / l).
In most patients with acute appendicitis, at the very beginning of the disease, the increase in the number of white blood cells in the blood is noted. In the catarrhal form of appendicitis, the leukocyte content in the blood is in the range of 10-12x109 / l, changes in the leukocyte blood formula are usually not observed. With phlegmonous appendicitis, the number of leukocytes in the blood reaches 12-20x109 / l, a regenerative shift of neutrophils with a high content of rod-shaped forms( up to 15%) is observed. With gangrenous form of appendicitis, the number of leukocytes is significantly reduced( up to 10-12x109 / L) or within the norm of 6-8x109 / L, but the inflammatory shift in the leukocyte blood formula can reach a significant degree [the content of the rod-shaped forms is 15-20% or more,the appearance of young neutrophils( 4-6%) and even myelocytes( 2%)].
When evaluating the results of a blood test for suspected acute appendicitis, it is necessary to adhere to the conclusions made by G. Mondre( 1996).
■ In cases without suppuration, leukocytosis does not exceed 15x109 / l.
■ If the leukocytosis does not cease to rise during the first 6-12 hours after an acute attack( a blood test is performed every 2 hours), one should beware of the rapidly spreading heavy infectious process.
■ Even if the general symptoms of the disease( pain, fever, etc.) seem to decrease, while leukocytosis continues to increase, the latter is more important, since fluctuations in the expression of leukocytosis at least 24 hours ahead of fluctuations in body temperature.
■ In exceptional cases, leukocytosis may be absent;the latter is observed when there is a sudden intoxication of the body or when the patient is severely depleted with a prolonged infection, or when the latter is localized and the abscess is drained and spontaneously sterilized.
A false increase in the number of leukocytes counted with an automatic analyzer is possible in the presence of cryoglobulinemia, clots or platelet aggregation or in the presence of nuclear forms of red blood cells( erythroblasts) or non-ligated red blood cells, which will be counted as leukocytes.
A number of acute infections( typhus, paratyphoid, salmonella, etc.) can in some cases lead to leukopenia. Especially this character
is thorny for the depletion of bone marrow reserves of neutrophils as a result of the use of modern chemotherapeutic agents, with nutritional deficiency or general weakening of the organism. Some bacteria and certain viruses( yellow fever, measles, rubella, chicken pox, etc.), rickettsia and protozoa can cause leukopenia in previously completely healthy people. The main causes of leukocytosis and leukopenia are reflected in the table.
Table Diseases and conditions accompanied by changes in the number of leukocytes
Table Diseases and conditions accompanied by changes in the number of white blood cells