RESUMO
Introduction: Platelets are anucleated cytoplasmic fragments derived from megakaryocytes, they are oval in shape, 1 to 2 millimeters in diameter, and have a half-life of 8 to 10 days. MPV is measured by automated cell counters based on impedance and optical effect, and can be modified by the anticoagulant ethylene aminotetraacetic acid (EDTA), temperature and storage time of the sample; Therefore, it is recommended that the analysis of the sample and its reading be carried out ideally in the first hour after taking the sample and preferably in the first 30 min. Another concept that is important to include in the interpretation of platelet activity is platelet mass, which is defined as the relationship between the platelet count and MPV; from which it has been found that the inverse platelet count-MPV relationship is not linear, so several normograms have been described to evaluate this relationship.3,4 The number, density and size of platelets is determined by a complex interaction between growth factors, cytokines, hormones and the megakaryocyte in the bone marrow. Megakaryopoiesis is programmed to maintain platelet function and mass, a mechanism in which thrombopoietin, granulocyte colony-stimulating factor, interleukins 1 and 6, and tumor necrosis factor are closely involved. Thrombopoietin levels are determined by gender and the number of platelets. In situations of stress, platelet production and mass are increased, resulting in the release into the circulation of large numbers of large, highly reactive platelets that migrate to sites of injury. An intense stimulus at the medullary level induces a hyperproduction of platelets that is characterized by a high MPV.