Abstract:

Objective To evaluate the accuracy of platelet count by UniCel DxH 800 Coulter hematology analyzer. Methods The results of platelet count by UniCel DxH 800 were compared with those of international reference method（flow cytometry）,according to the Clinical and Laboratory Standards Institute（CLSI） EP9-A2. A total of 556 ethylene diamine tetraacetic acid-K₂（EDTA-K₂） anticoagulant specimens were collected,including 113 specimens with platelet count <50.0×10⁹/L and 36 specimens with giant platelets by manual identification. All specimens were analyzed by UniCel DxH 800 and Coulter EPICS XL flow cytometry using CD41 and CD61,respectively. Results The results of platelet count by UniCel DxH 800 were in good correlation with flow cytometry （correlation coefficient was 0.994 3）,even for specimens with platelet count <50.0×10⁹/L （correlation coefficient was 0.948 0）. The biases for specimens with extremely low platelet count （<20×10⁹/L）,moderately low platelet count [（20-50）×10⁹/L],low platelet count [（50-100）×10⁹/L],normal platelet count [（100-275）×10⁹/L] and high platelet count（>275×10⁹/L） were 2.2%,2.5%,1.0%,0.6% and -1.7%,respectively,which were all lower than expected bias（12.5%）. For specimens with giant platelets,the correlation coefficient of the 2 methods was 0.986 8. Conclusions Platelet count obtained from UniCel DxH 800 is accurate at all critical levels and even in the presence of giant platelets.

Key words: Hematology analyzer, Flow cytometry, Platelet count, Performance evaluation