Comparison of various diagnostic methods in assessing platelet count in patients with immune thrombocytopenia

Introduction: Accurate platelet count (PLTC) in immune thrombocytopenia is important in order to make therapeutic decisions. The basic method of assessing PLTC is peripheral blood morphology with EDTA or with citrate. The older way of assessing PLTC is measurement under the microscope (FONIO), and the newer way is the fluorescent method. The purpose of this study was to compare PLTC methods, and find the most reliable. Material and methods: PLTC was assessed using five methods in adult patients with previously untreated ITP (EDTA, citrate, FONIO, fluorescent, and immunofluorescent methods). Results: 66 patients were enrolled in the study. The median age was 56 and 56% were men. Median PLTC in EDTA was 69 G/L, in citrate 69 G/L, in fluorescence 69 G/L, in FONIO 90 G/L, and in immunofluorescence 83 G/L. A significant difference in PLTC was observed in comparing EDTA to immunofluorescence (53% ±123%), followed by FONIO (51% ±91%). PLTC from immunofluorescence differed from the fluorescent method by 40% ±78%. Conclusions: The most valuable method for obtaining PLTC is the immunofluorescent method. These findings are especially important in helping to make therapeutic decisions during a challenging time for accessing medical care like a pandemic.