Evaluation of leukocyte differential counts on the QBC centrifugal hematology analyzer according to NCCLS standard H20-T.

A performance study of the QBC centrifugal hematology system was conducted according to reference and analytical procedures defined in NCCLS Tentative Standard for Leukocyte Differential Counting, H20-T. A complex mathematical transformation and analysis of variance (ANOVA) were applied to the test data. This statistical technique is intended to segregate and emphasize differences in samples and methods. The comparative study of leukocyte differential counts show that QBC is equivalent in performance to the NCCLS reference method when the latter counts are grouped according to the WBC subpopulations reported by QBC. Within these grouped subpopulations, QBC counts were more precise than manual reference counts and otherwise comparable in terms of results. Similarly, QBC compared favorably with the reference method in its clinical sensitivity to abnormals, based on between-method versus within-method studies of hospital specimens.