Mean Platelet Volume, Platelet Distribution Width, and Platelet Count, in Connection with Immune Thrombocytopenic Purpura and Essential Thrombocytopenia

OBJECTIVE: To examine the kinetic characteristics of platelet (PLT) destruction and thrombopoiesis by using mean platelet volume (MPV) and platelet distribution width (PDW). METHODS: Using the ADVIA2120i instrument, we measured PLT counts, MPV, and PDW in 153 healthy individuals, 35 patients with immune thrombocytopenic purpura (ITP), and 48 patients with essential thrombocytopenia (ET). RESULTS: In the ITP group, the MPV and PDW were higher than those values in healthy individuals. In the ET group, the MPV was lower than in the ITP group and in healthy individuals, and the PDW was lower than in the ITP group. When the ITP group was subdivided (PLT counts <45 × 103/µL vs ≥ 45 × 103/µL), the MPV and PDW tended to be higher in patients with PLT counts less than 45 × 103 per µL. When patients with ET were subdivided (PLT counts <770 × 103/µL vs ≥770 × 103/µL), the MPV and PDW were lower in patients with PLT count of 770 or greater × 103 per µL. CONCLUSIONS: In ITP, the overall PLT composition varies, and PLT sequestration is nondiscriminatory. In ET, PLTs quickly shrink and remain small, resulting in a high proportion of small-sized PLTs.