[Automated platelet count in thrombocytopenic patients--a comparison of methods]

157 EDTA blood samples from thrombocytopenic patients (platelets less than 100 X 10(9)/1) were measured and the platelet counts compared using the various blood cell counters of the central laboratory, University Clinic, Göttingen. Using the H 6000, Hemalog 8 (both Technicon) and ELT-8 (Ortho Instruments), product-moment correlation coefficients (r) ranging from 0.88 to 0.92 were obtained between the different counters. The correlation coefficients of the thrombocounter (Coulter) to the other instruments were only 0.84 and 0.85. Discrepant platelet counts (difference greater than 40 X 10(9)/1) were reinvestigated using the Neubauer chamber. From a total of 354 platelet measurements, falsely high concentrations were observed only in three cases and falsely low concentrations in seven cases.