Increased values of mean platelet volume and platelet size deviation width may provide a safe positive diagnosis of idiopathic thrombocytopenic purpura.

Introduction: It has been shown recently that platelet indices like mean platelet volume (MPV), platelet size deviation width (PDW) and platelet-to-large-cell ratio (P-LCR) are helpful in the discrimination between hyperdestructive thrombocytopenia like idiopathic thrombocytopenic purpura (ITP) and hypoproductive thrombocytopenia (HT). The aim of the study is to assess the reliability of these indices in the differentiation of ITP from other thrombocytopenias.

Methods: We recruited 134 thrombocytopenic patients (69 men, 65 women) who were divided into two groups according to the underlying disease: group I (n = 63) included ITP patients, whereas group II (n = 71) included patients with HT due to myelosuppression secondary to chemotherapy for hematological malignancies. Platelet indices were derived from a Sysmex automated cell counter. Sensitivity, specificity, positive prognostic value, negative prognostic value, efficiency and Youden index were calculated.

Results: Concerning MPV and PDW indices, sensitivity, specificity, positive prognostic value, negative prognostic value, efficiency and Youden index were 100% for the diagnosis of ITP. On the contrary, the values for P-LCR were significantly lower.

Conclusions: MPV and PDW can be safely relied on for a positive diagnosis of ITP. MPV and PDW were superior to P-LCR.