It used to be considered that the number of leucocytes counted by the counting chamber method and the smear preparation gave a good estimate of the number of leucocytes in the body.
Depending on the method and the instruments used, errors might result when examining a drop of body blood or several drops.
This study with whole blood compares its result with ordinary methods.
1) Blood was taken from the cubital veins of normal healthy students and was counted by a dilution method and also 1 cu. mm. was used to make a smear preparation.
2) The difference between the dilution method and the smear method differed as much as 16%. More leucocytes were obtained by the dilution method than by the -smear preparation.
3) To get a better value of the percentages of leucocytes, 100, 200, 300, 400, 500, 1,000, 2.000, 3.000, 4.000 and 5.000 leucocytes were counted in a cu. mm. of blood. Percentages along with the mean values were calculated. Errors were considered as 2 the mean value.
4) To lessen the amount of errors which varied±20% in neutrophil and lymphocytes calculation 300-400 leucocytes should be counted.
5) There is a±20% error in eosinophil counting so 1000-2000 leucocytes should be counted in the smear preparation & 8-12 chambers(3X3X0.lmm) in the dilution method with hunger´s solution.
6) The smear preparation for eosinophils gives a f 50 % error which makes it of little use.
7) Mean value of the nuclear number was calculated as 2.56, which should be correct for counting
100 leucocytes.
8) Correlation coefficient calculated by the total number of leucocytes and the analytical number of leucocytes was observed and the coefficient between the above mentioned numbers showed that neutrophils, basophils and menocytes had a 1% level of significance, and lymphocytes a 5% level of significance. There was no constant factor in eosiniphil which showed much individual difference due to various stimuli.
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