The high amount of platelets has important implications in diagnosis and treatment of the patients.  In the present study, lt could be proven the utility of the index MPV, (Mean platelet volume) and the PDW (variation in platelet size distribution) in the platelet diseases.  We found 45% pediatric patients with reactive thrombocytemia alterations in the VPM, in the PDW or in both, in comparison with the values that were obtained in the control group.  They present platelets with smaller size and with more heterogeneity lt is important to consider these available parameters at the moment, in order to heip in the differential diagnosis of thrombocytosis at the first line.

platelets; platelet volume; platelet heterogeneity; thrombocytosis