Evaluation of the leukocyte differential flags on an hematologic analyzer. The Cobas Argos 5 Diff.

To evaluate the leukocyte differential flags of the Cobas Argos 5 Diff., the authors performed a comparative study between their current analyzer, the Technicon H2, and the manual leukocyte differential. Samples (n = 1,600) were collected from the Blood Disease Department of their hospital and were tested on both Cobas Argos 5 Diff. (ABX/Roche Hematology Division, Montpellier, France) and Technicon H2. Abnormalities of the manual leukocyte differential (immature granulocytes, blast cells, atypical lymphocytes, hyperbasophil cells, erythroblasts, and hairy cells) were found in 597 samples. The authors determined the best cut-off of the quantitative flags--atypical lymphocytes (ALYs) and large immature cells (LICs)--using the likelihood ratio method, and the capability of the 5 Diff. qualitative flags to determine abnormal subpopulations by the predictive value of a positive result. The presence of particular combinations of flags was associated with band cells and blast cells of acute lymphoblastic leukemia (ALL) or acute myeloblastic leukemia (AML). The sensitivity, specificity, and efficiency of the two analyzers were 92.1, 53.9, and 68.2, respectively, for the Argos 5 Diff., and 93.5, 36.7 and 57.9, respectively, for Technicon H2. In conclusion, the Cobas Argos 5 Diff. is well adapted for detecting leukocyte abnormalities.