The Utility of Platelet Indices in Differentiating between Hyper-productive and Hypo-productive Thrombocytopenia in Children

Abstract

background: Thrombocytopenia refers to a reduction in platelet count to <150 × 109/L. It may occur due to decreased production) hypoproductive thrombocytopenia) such as aplastic anemia (AA) and acute leukemia (AL), or increased destruction of normally synthesized platelets (hyperproductive thrombocytopenia) such as immune thrombocytopenic purpura (ITP). Platelet indices, namely plateletcrit (PCT), mean platelet volume (MPV), platelet distribution width (PDW), platelet –large cell ratio (P-LCR) and immature platelet fraction (IPF) .Platelet Volume Indices (PVIs) are a group of parameters which are inexpensive to measure and are derived from routine blood counts.Objective In this study, we aimed to assess the sensitivity and specificity of these indices and set cutoff values that aid in diagnosis of thrombocytopenia causes.Patients and Methods: We recruited 90 individuals as thrombocytopenic patients, who were divided into two groups: group I (n= 40) included newly diagnosed immune thrombocytopenic purpura (ITP) patients (hyperproductive thrombocytopenia), whereas group II(n = 50) included hypoproductive thrombocytopenia patients. The MPV and PDW were derived from automated cell counter. A comparison of the sensitivity and specificity for MPV and PDW in both conditions (hypo and hyper-production thrombocytopenia) were evaluated.Results: All platelet indices were significantly higher in ITP than in ( AA and AL), and platelet indices showed sufficient sensitivity and specificity ; the best cutoff value for MPV was greater than 10.6 fl and for PDW was greater than 16fl, with a sensitivity(90,95) and specificity(86,80) respectively.. The area under the curve (AUC) of the receiver operating characteristics curve of platelet indices was large enough to enable the diagnosis of ITP. the PDW had the larger AUCs(0.938)than MPV where AUCs (0.900) , which means that these values are very reliable for ITP.Conclusion: Platelet volume indices can differentiate with some certainty ITP from AL and AA, and helps pediatricians to avoid the invasive bone marrow aspiration which need expert hematologist for its interpretation.