CLINICAL-PERFORMANCE OF LEUKOCYTE DIFFERENTIAL ON THE NEW ROCHE-COBAS-VEGA HEMATOLOGICAL-ANALYZER

The Roche Cobas Vega is a five-part differential haematological analyz er evolving from the former Cobas Hellos, Argos and Micros. As the leu kocyte differential of Cobas Vega displays several interesting feature s, we analyzed its clinical performance and compared it either to thre e other commercial haematological analyzers (Technicon-Bayer H2, Coul ter STKS and Abbott CD-3500) or to the manual reference method, as des cribed in the National Committee for Clinical Laboratory Standards (NC CLS) H20-A protocol. Within- and between-batch coefficients of variati ons (CVs) of the white blood cell differential were satisfactory and c lose, or even better than the ones reported for the other instruments: 0.81% (neutrophils), 1.87% (lymphocytes), 6.76% (monocytes), 7.73% (e osinophils) and 22.55% (basophils). The identification of abnormalitie s in the while blood cell differential was obtained either on the basi s of the instrument-specific ranges or on the generation of one or mor e flags by comparison with results of the manual reference method. The Vega demonstrated remarkable performance in terms of specificity (90. 0%), sensitivity (91.6%) and both positive (97.7%) and negative (69.1% ) predictive values; likewise, the global efficiency was the best (90. 3%) among the analyzers we evaluated. The flags generated in the prese nce of morphological abnormalities of the samples displayed excellent sensitivity (from 88.9% to 100%), specificity (from 93.5% to 98.3%) an d satisfactory positive (from 51.1% to 66.7%) and negative (from 98.3% to 100%) predictive values. We conclude that the analytical performan ce of the new Cobas Vega haematological analyzer can significantly imp rove the identification of various haematological abnormalities as an important contribution to the accuracy is provided by the new staining for granulocytes.