A NEW METHOD FOR COUNTING BLOOD PLATELETS AND RELATION OF RESULTS OF THIS METHOD AND NORMAL VALUE

Abstract

The advantages and disadvantages of the direct and indirect methods of counting blood platelets are subject to discussion, but factor of simplicity and long term preservation bring to the foreground the use of Fonio's method. However, failure attending this method in obtaining uniform distribution of the blood platelets and the erythrocytes in the blood smears may be pointed out. Therefore, as a modification of the smear technic and the character of the diluent used, a cover glass method of obtaining more uniform distribution of blood platelets and erythrocytes was conceived. As compared with Fonio's method, the number of blood platelets counted by the new method is definitely larger, and the normal value is found to be 520, 000 per cmm, a value believed to approach more closely the actual count.
The characteristics of the new method are as follows:
1) The viscosity of the diluent is rendered high as to give a uniform distribution of the erythrocytes and the blood platelets.
2) The staining of the blood platelets is improved through altering the pH of the diluent to an alkaline character.
3) Counting can be made immediately without fixation or staining.
4) This technic is simple and the rate of destruction and agglutination of the blood platelets is low, thus giving more accurate values.
5) The count is more stable as compared with Fonio's method.
6) The blood platelets and the reticulocytes may be counted at the same time.
The foregoing are the advantageous features of the new method, but a disadvantage is that fresh blood samples must be used, for which preservation must not exceed 24 hours, and special care in this respect must be taken in obtaining and counting of blood samples.