Diagnostic value of the Hemalog D-90 in classifying acute childhood leukaemias.

Accurate classification of the acute leukaemias is dependent not only on morphological characteristics, but also on cytochemical staining properties of the blasts in peripheral blood and bone marrow. This study was undertaken to evaluate the Hemalog D-90, an automated cytochemistry system for white cell differential counts, as an adjunct to conventional microscopy in the classification of acute childhood leukaemias. Fifty-two patients were classified according to morphology and cytochemical reactions of the cells obtained from peripheral blood. In 29 with classical acute lymphoblastic leukaemia (ALL), the Hemalog D showed the lymphoblasts to be non-peroxidase staining and these were recorded mainly as lymphocytes. In contrast, the blasts of eight patients with acute myeloblastic leukaemia (AML) were peroxidase positive, being recorded as neutrophils. Of the remaining 15 patients, 10 were classified as "Probably ALL' because they lacked some of the morphological or cytochemical criteria for classical ALL, while five were unclassifiable. However, in all these 15 patients the Hemalog D results were similar to those obtained in patients with classical ALL. We concluded that the Hemalog D was a useful adjunct in distinguishing ALL from AML, including the morphologically indistinct types.