Leukocyte blood formula
Leukocyte formula - the percentage ratio of different types of leukocytes in the blood smear. Reference figures are shown in Table., From which it appears that during the neonatal cells ratio is very different from that in adults [Nikushkin EV, Kryuchkov, MI, 1998].When evaluating the leukocyte formula, it may be necessary to take into account the absolute content of certain types of leukocytes.
Changes in the leukocyte formula accompany many diseases and are often nonspecific. Nevertheless, the diagnostic value of this study is great, as it gives an idea of the severity of the patient's condition, the effectiveness of the treatment. With hemoblastoses, the study of the leukocyte formula often allows you to establish a clinical diagnosis. The main causes leading to changes in leukocyte counts, are shown in Table. .
Table Diseases and conditions are accompanied by a shift leukocyte
Table Diseases and conditions are accompanied by a shift
leukocyte In many severe infections, septic and purulent processes wbc varies duean increase in the number of rod-nuclear neutrophils, metamyelocytes and myelocytes. Such a change in the leucogram with increasing percentage of young forms of neutrophils is called the left shift;The increase is mainly due to segment-nuclear and polysegment-nucleus forms - a shift to the right. Severity of neutrophil nuclear shift is estimated by the shift index( IC).IP + MM = M + F / N, where M - myelocytes, MM - metamyelocytes, P - stab neutrophils, C - segmented neutrophils. The reference value of the IC is 0.06.The value of IP is an important criterion determining the severity of acute infection and a general prognosis.
When analyzing the results of calculating the leukocyte formula in a blood smear, it should always be remembered that this method is not very accurate and can be a source of errors that can not be completely eliminated( including
tea mistakes when taking blood, preparing and dab smearing, human subjectivity in interpretingcells).Some types of cells, especially monocytes, eosinophils and basophils, are distributed in a smear completely illegally. The high content of these cells, especially in the restricted area of the smear, must be rechecked before the result is issued. When the number of leukocytes in the blood is more than 35x109 / l, it is recommended to count at least 200 cells for greater accuracy. The number of leukocytes examined should increase in proportion to the increase in leukocytosis in order to assess the large area of the smear. If the number of leukocytes in the blood is less than 2 x 109 / l, then some laboratories count less than 100 cells. However, the accuracy is sharply reduced, so this calculation is not recommended. If you can not find in a smear of 100 cells, it is proposed to do leukoconcentrate, but it should be remembered that in the preparation of the last occurring morphological changes of leukocytes and the uneven distribution of cell types. If less than 100 or more than 100 cells were counted, this should be reflected in the result form.
A confirmation of the fact that the method of calculating the leukocyte formula in a blood smear is not very accurate, see the table.data of 95% confidence interval when calculating the leukoformula, obtained on the basis of statistical analysis.
Table 95% confidence interval when calculating the leukoformula in a blood smear [E.Anne Stiene-Martin et al., 1998]
Table 95% confidence interval when calculating leukoformula in a blood smear [E.Anne Stiene-Martin et al., 1998]
Widespread to assess the degree of intoxication received endogenous leukocyte intoxication index( LII), the reference value for that is about 1.0.The formula for the calculation is as follows.
LII = [4( myelocytes) + 3( metamyelocytes) + 2( band neutrophils) +( segmented) x( plasma cells + 1)] / [(lymphocytes + monocytes) X( eosinophils + 1)]
Fluctuations LII patientswith infectious and septic diseases objectively correspond to changes in the clinical picture and the degree of expression of endogenous intoxication. The increase in LII to 4-9 indicates a significant bacterial component of endogenous intoxication, a moderate increase( up to 2-3) - either limiting the infectious process or the focus of necrobiotic tissue changes. Leukopenia with high FII is an alarming prognostic sign. LII can be used to assess the effectiveness of the treatment.