[Discrepancy of platelet numbers between automated blood cell analysis and manual counting in the patients with thrombocytopenia].

Automated blood cell analyzer can measure the numbers of blood cell and a histogram patterns of WBC, RBC and Platelet (PLT), and calculate the blood cell indices (RDW, MPV, PDW, etc). It is important clinically in the patients with thrombocytopenia (below 10 x 10(4)/microliter) to measure correct platelet number. However platelet number with automated blood cell analyzer was influenced by the changes in erythrocyte morphology or various PLT conditions. We subclassified the patients with thrombocytopenia into 5 groups according to the histogram pattern of PLT, and compared platelet numbers among NE-8000 analysis (Sysmex), H2 analysis (Bayer's) and manual method in each group. In the group of abnormal histogram pattern of PLT, platelet numbers obtained with NE-8000 or H2 were significantly low comparing to manual numbers. About 70% of samples of which Platelet Distribution Width (PDW) was abnormal showed discrepant values between automated analysis and manual eye count. In conclusion, discrepant low platelet count would be obtained by automated analysis and therefore should be carefully interpreted in the patients with thrombocytopenia and abnormal platelet histogram pattern.