[An evaluation of automated hematology analyzers in detecting abnormal blood cells]

We report the usefulness and capability of two hematology analyzers with different principles in characterization of abnormal cells such as immature granulocytes and blasts. We studied a total 1635 specimens which included 69 cases with hematopoietic malignancies. THMS H-1 (Technicon Instruments) and NE-8000 (Toa Instruments) were used as analyzers. An effort was made to determine the sensitivity and specificity of positive abnormal cell flag in comparison with the presence of abnormal cells seen on a manual differential. True positive rate for immature granulocytes in H-1 and NE were 43% and 30%, respectively. False positive rate for immature granulocytes in H-1 and NE were 0.01% and 0.03%, respectively. With both analysers, cases with low percentage of immature granulocytes generated negative flag for abnormal cells. True positive rate for blasts in H-1 and NE were 74% and 65%, respectively. False positive rate for blasts in H-1 and NE were 1.8% and 0.2%, respectively. With both instruments, in all cases with blast count over 100/microliters, blasts were detected. Only H-1 detected the cases with blast counts less than 100/microliters. In H-1 all cases with ATL, one case with AMMoL and another with ALL generated negative blast flag. Upon morphologic examination, these blasts were found to be large and peroxidase negative with convoluted and irregularly shaped nuclei. On the other hand, NE detected blasts regardless of those morphology. In conclusion, Both instruments are useful in screening abnormal blood cells, while their unique capability must be considered.