Role of Platelet Indices in Determining the Type of Thrombocytosis

BACKGROUND We wanted to evaluate the role of platelet indices in differentiating reactive and clonal thrombocytosis. METHODS This is a cross sectional observational study conducted for two years among 150 patients with platelet counts of 5 lac and above. Thrombocytosis and utility of platelet indices like Mean Platelet Volume (MPV), Platelet Distribution Width (PDW) for the differential diagnosis of thrombocytosis were done. RESULTS Out of total 150 cases, 144 (96 %) had reactive thrombocytosis, and 6 (4 %) had clonal thrombocytosis. Infectious aetiology is seen in 64 (42.6 %), tissue injury 35 (23 %), rebound thrombocytosis 22 (14.6 %), anaemia 13 (8.6 %), multiple causes 8 (5.3 %), clonal aetiology 6 (4 %), and inflammatory 2 (1.3 %). Patients with reactive thrombocytosis showed a lower mean platelet volume and platelet distribution width compared to primary thrombocytosis. In reactive thrombocytosis MPV range, 6.0 - 8.0 fl with mean MPV 6.5 fl and PDW ranges from 14.0 - 16.2 % with mean PDW 15.3 %. In clonal thrombocytosis MPV range, 6.9 - 8.5 fl with mean MPV 7.9 fl and PDW range was 15.9 - 17.2 % with mean PDW 16.4 %. CONCLUSIONS On analysing the platelet counts and indices, patients with high counts, low MPV and PDW suggested reactive aetiology and patients with high counts and high MPV and PDW suggested clonal aetiology. KEYWORDS Thrombocytosis, Mean Platelet Volume, Platelet Distribution Width