Features of the leukocyte formula in childhood
The leukocyte formula is an indicator of the state of peripheral blood, reflecting the percentage of leukocyte cells of different types. Normally the ratio of leukopoietic cells has characteristic features depending on the age of the child.
In healthy newborns, leukocyte shift with a shear index of 0.2 (normal in adults 0.06). At the birth of a child in the formula 60-65% leukogram is represented by neutrophils and 30-35% lymphocytes. By the end of the first week of life, the number of these cells is equalized
45% and the first cross-over of the leukocyte formula occurs and by 10-14 days in the blood of a newborn physiological lymphocytosis is formed. The content of lymphocytes in the leukocyte formula is 55-60%. In addition, an increase in the number of monocytes to 10% is typical. The second cross in the leukocyte formula occurs in 5-6 years, after which, by the age of 10, the blood leukogram acquires the features of an adult:
- stab neutrophils – 1-6%,
- segment neutrophils 47-72%
- lymphocytes 19-37%,
- monocytes 6-8%,
- eosinophils 0.5-5%,
- basophils 0-1%.
A sharp increase in the number of lymphocytes in the blood in the first week after birth and their predominance in the white blood formula to 5-6 years of age is a physiological compensatory mechanism associated with the pronounced stimulation of the child’s body by antigens and the development of the immune system of the child. According to several authors, an earlier intersection in the leukocyte formula, a tendency to eosinophilia, relative neutropenia, and an increase in the number of lymphocytes are being observed.