EVALUATION OF THE ABX-COBAS-VEGA-AUTOMATED-HEMATOLOGY-ANALYZER AND COMPARISON WITH THE COULTER-STKS

An evaluation of the new automated hematology analyzer was performed i n comparison with the Coulter STKS on 1,694 blood samples coming from the different departments of Nice University Hospital. The Cobas Vega showed very satisfactory results in terms of repeatability, reproducib ility and linearity. Correlation with the STKS was excellent with the exception of the following parameters: red blood cell distribution ind ex and the absolute values for eosinophils and basophils. Two qualitie s were particularly appreciable: absence of leukocyte carryover, and s tability of the complete blood count and leukocyte differential count over a long period. Analysis of qualitative flags showed that the over all blood smear review rate was 47% for the Cobas Vega, not forgetting that optical microscopy detects 37% of all abnormalities. The STKS's review rate was 49.5%. Flags commonly concerned the granulocytic linea ge, 61% for the STKS and 48% for the Vega, with a false positive rate of 43.4% for the STKS compared with 22% for the Vega. The opposite phe nomenon was observed with the flag for atypical lymphocytes which repr esented 11% of flags for the STKS and 25.6% for the Vega, with a false positive rate of 25.5% for the STKS and 34% for the Cobas Vega. This may be explained by the fact that lymphocyte abnormalities sometimes g enerated ''granulocytic'' flags on the STKS. Studies of the false nega tive rate carried out using light microscopy on 505 blood samples with out flags on either system, detected the presence of a slight myelemia , and a few hyperbasophilic lymphocytes or plasmocytes in 18.6% of all cases. Finally, the Cobas Vega's practicality was greatly appreciated and there was no trouble with breakdowns throughout the whole period of its use.