Platelet indices in the differential diagnosis of thrombocytosis

Objective: To assess the role of platelet indices mainly: Mean Platelet Volume (MPV) and Platelet Distribution Width (PDW) for the differential diagnosis of thrombocytosis.Methods: A prospective case series study conducted at Ibn–Sena Teaching Hospital in Mosul during the period from June 2003 to January 2005. Ninety two patients with thrombocytosis were analyzed for platelets indices using Coulter MS-9. A control group of sixty normal subjects were also included in this study for comparison.Results: Thrombocytosis was found to be due to two main causes: 12 patients with myeloproliferative disorders, and 80 patients had secondary reactive causes of thrombocytosis. Patients with myeloproliferative disorders had significantly higher Mean Platelet Volume (MPV) than those with reactive thrombocytosis. Also the Platelet Distribution Width (PDW) was higher in patients with myeloproliferative disorders than those with reactive thrombocytosis and control group.Conclusion: Platelet indices especially PDW seem to be a good variable for the differential diagnosis of thrombocytosis.Keywords: Thrombocytosis; platelet indices Mean Platelet Volume (MPV); Platelet Distribution Width (PDW).