Diagnostic utility of platelet indices and serum thrombopoietin in differentiating immune and hypoproliferative thrombocytopenia in children

BACKGROUND: Thrombocytopenia is broadly classified, based on underlying etiology, into thrombocytopenia due to peripheral platelet destruction and those due to bone marrow hypoproliferation. In recent years, platelet indices and serum thrombopoietin (TPO) have gained attention as potential noninvasive markers reflecting platelet production and turnover. OBJECTIVES: The present study aimed to assess the diagnostic usefulness of platelet indices and serum TPO levels in distinguishing immune thrombocytopenia (ITP) from hypoproliferative thrombocytopenia secondary to aplastic anemia or chemotherapy-induced thrombocytopenia (AA/CIT) in children. MATERIALS AND METHODS: This prospective case–control study involved 60 pediatric patients (aged 2–16 years) with thrombocytopenia: 34 children with newly diagnosed ITP and 26 children with thrombocytopenia due to AA/CIT, with 23 healthy children included as a control group. Platelet indices were measured using an automated hematology analyzer, and serum TPO concentrations were determined by enzyme-linked immunosorbent assay. RESULTS: Platelet count and plateletcrit were significantly higher in controls than in thrombocytopenic patients ( P < 0.001). Serum TPO was markedly elevated in the hypoproliferative group compared with the ITP group and controls ( P < 0.001). Conversely, immature platelet fraction (IPF), platelet–large cell ratio (PLCR), and mean platelet volume (MPV) were significantly higher in ITP ( P < 0.001). CONCLUSIONS: Elevated TPO level can be a useful marker for identifying hypoproliferative thrombocytopenia, while elevated IPF, PLCR, and MPV favor ITP. These parameters may have value in identifying the underlying pathophysiological mechanisms of thrombocytopenia.