Estimate of Thrombopoiesis by Flow Cytometric Analysis of Reticulated Platelets in Moderate Thrombocytopenia

Won, Dong Il; Suh, Jang Soo; Lee, Won Kil

Abstract

BACKGROUND
Measurement of reticulated platelets (RPs) is useful in order to discriminate the causes of thrombocytopenia. In flow cytometric analysis for the percentage of RPs (RPs%), only thiazole orange (TO) fluorescence is considered, ignoring the significance of forward scatter (FSC). In this study, we intended to devise a new index reflecting the pattern of platelet clusters in the plot of FSC vs. TO fluorescence. METHODS: In the patients with moderate thrombocytopenia, 44 cases with decreased thrombopoiesis and 37 cases with increased thrombopoiesis were selected. In flow cytometry, several indices made with FSC and TO fluorescence were evaluated in discrimination between the two groups. RESULTS: Of the primary parameters, RPs% and FSC had relatively high efficiencies in discrimination. A new index incorporating these two parameters had higher efficiency than RPs% (P<0.05). New index=RPs%x(TO-positive platelet FSC-TO-negative platelet FSC)/TO-negative platelet FSC) CONCLUSIONS: In addition to the RPs%, more information about thrombopoiesis was obtained through the analysis of the plot of FSC vs. TO fluorescence and the index that quantifies the pattern of TOstained platelet clusters was devised.