Automated counting of platelets on the Bayer ADVIA 120 analyser

Precise counting of platelets is difficult particularly in the low thrombocytopenic range or when large platelets exist. The recently available Bayer ADVIA 120 analyser uses a method of counting platelets based on two dimensional laser light scatter. We have evaluated this technique on an analysis of 217 peripheral blood samples and found significant differences in platelet counts compared with values obtained by impedance technology, when the causes of thrombocytopenia were due to peripheral platelet consumption. Moreover, such differences were more marked in those samples from severely thrombocytopenic individuals with large platelets on the blood film. These differences, which warrant further study, may have significant implications for the management of patients with very low platelet counts.