[Automated blood cell measurements: a comparison between the Bayer H2 and the Abbott Cell-Dyn 3500]

We have compared two hematologic analyzers, H2 (Bayer) and CELL DYN 3500 (Abbott). The protocol we used was able to evaluate the overall analytical quality, the effect of aging of the sample on the measured parameters, the quality of leucocytes differential count. Number and quality of information supplied for each sample by both analyzers were then taken in account.

Excellent correlation for all measured parameters was found: only monocytes were, albeit modestly, overestimated by CELL DYN 3500 compared to H2. Ageing of sample and temperature of storage had a marked effect on CELL DYN's measurements, resulting in impaired recognition and classification of leucocytes, while the results for the other parameters were acceptable. Comparative evaluation of the differential count of leucocytes was made between the results of both analyzers and microscopic examination. While specificity, predictive value of negative results and quantity of false negative results were practically the same, sensitivity, predictive value of positive results and quantity of false positive results were better for H2 as compared to CELL DYN (87.1% vs 78.1%, 79.4% vs 65.8, 7 vs 13, respectively). The clinical utility of supplementary informations (alarms, flags, cytograms, etc.) yielded by the analyzers was relevant for H2 regarding the erythrocytes cytograms, for CELL-DYN 3500 regarding the application of the extended lyse program for lytic resistant RBCs and of the Vet Package.

CELL DYN 3500 performance have on the whole confirmed the producer's claims, being of reliable use in the haematological screening on account of its simplicity and more than good overall analytical quality.