Comparison of Automated Platelet Counts and Potential Effect on Transfusion Decisions in Cancer Patients.

Objectives: To evaluate the accuracy of platelet counts from various hematology analyzers using a reference immunologic method. Methods: We tested 403 samples with platelet counts less than 50 x 109/L with the Advia (Siemens, Tarrytown, NY), Sysmex (Mundelein, IL), and Abbott (Santa Clara, CA) analyzers. Results: All methods showed a positive bias, especially at less than 20 x 109/L and less than 10 x 109/L. Undertransfusion risk ranged from 9.1% to 43.3 % in the groups below 20 x 109/L and below 10 x 109/L, respectively. For patients with optical counts more than 10 x 109/L and CD61 less than 10 x 109/L, 64.5% were transfused within 24 hours of the reported count, while 35.5% were transfused in more than 24 hours, after a subsequent optical platelet count of 10 x 109/L or less was reported. Conclusions: Although optical and impedance methods were shown to be falsely increased in severely thrombocytopenic samples, further studies are needed to determine if more accurate methods would be clinically useful. [ABSTRACT FROM AUTHOR]