A method for the detection of abnormal leukocytes using cytochemical criteria

An alarm system for the detection of abnormal leukocytes using off-line data processing of the image of the peroxidase channel oscilloscope picture of the Hemalog-D is presented. The basic idea is that areas on the oscilloscope picture where more than a negligible number of nonpathological leukocytes may be depicted are delimited from the remaining area, which is divided into three alarm zones. The corresponding alarm quantities are the large unstained cells (LUC) or the unstained alarm (UA), the intermediate alarm (IA), and the stained alarm (SA). Reference intervals for these alarms were established using blood specimens from 15 healthy subjects. The system was tested using blood specimens from four patients with acute lymphoblastic leukemia (ALL) and 11 patients with acute myeloblastic leukemia (AML). The UA was the best alarm overall, but for seven of the AML specimens the IA or the SA alarm was superior. The high peroxidase (HPX) and the remainder alarms were inferior to the other alarms. Using the reference mean plus two standard deviations as a cutoff value, the smallest blast cell number fraction detectable by the best alarm was calculated to be smaller than 2% for each of the AML specimens, while it ranged from 7 to 2.9% for the ALL specimens.