Some Observations on Peroxydase Reaction of Leukocytes

The improved method of peroxydase reaction for human leukocyte analysis was studied comparing with the recommended clinical laboratory methods. This new method ”Benzidine-Zinc Method” differs from others in the pretreatment with ZnSO_4 solution, although it principally depends on the oxydation of benzidine by the peroxyde-peroxydase system. The main procedures of this method are following in order, fixation with 10% formalin-alcohol, Giemsa staining, 1% ZnSO_4 treatment and the benzidine-peroxide reaction lastly. The specificity of this reaction to leukocyte peroxydase was confirmed by careful comparison with the results of Sato-Sekitani's and Mc Junkin's methods. It is found that this method is more excellent at three points. First, the reaction products in blood cells are observable very clearly, that is intense blue in neutrophils, yellowish brown in acidophils and faint blue in monocytes. Secondly, identification of blood cell types is very easy according to per-staining wiith Giemsa solution. Thirdly , red corpuscles and blood platatelets are well preserved, and the pseudo-peroxydase reaction in red cells is negrigible. This method was applied to some Patients with leukemia and others, and the results obtained were discussed. Thus this ”Benzidine-Zinc Method” of peroxydase reaction seems to be reliable and excellent for clinical laboratory use.