[Precision and accuracy of white blood cell differentiation by an automated blood cell analyzer]

Precision and accuracy are important to assure the quality of clinical laboratory tests. We investigated the precision and accuracy of white blood cell (WBC) differentiation by automated blood cell analyzers. The coefficients of variation (CVs) of neutrophil, lymphocyte, monocyte, eosinophil and basophil differentiation by GEN.S (Coulter), based on a flow system and VCS technology, were 1.1%, 1.5%, 4.6%, 2.1%, and 33.3%, respectively. Between-run precision for neutrophil, lymphocyte, monocyte, eosinophil and basophil differentiation by GEN.S using cell control, 5C in 26 serial days was 2.0%, 2.8%, 6.5%, 9.2%, and 29.5%, respectively. The precision of WBC differentiation by blood cell analyzers based on the flow system was excellent except for basophil. We studied the accuracy of WBC differentiation by blood cell analyzers based on the flow system in contrast with eye-count. The correlations between neutrophil, lymphocyte, monocyte, eosinophil, and basophil percentages counted by GEN.S and by eye-count were r = 0.968, 0.971, 0.902, 0.940, and 0.391, respectively. The agreement rate between WBC differentiation by Microx, a blood cell analyzer based on pattern recognition, and eye-count cell by cell was good except for basophils. The accuracy of WBC differentiation by blood cell analyzers was also excellent excluding basophils.