[Diagnostic significance of the number of bone marrow megakaryocytes in cases with decreased platelet production evidenced by platelet kinetic study].

In 18 patients with decreased platelet production proved by reduced platelet turnover, the numbers of megakaryocytes in clot section of marrow aspirate were counted. Platelet counts ranged from 19,000 to 128,000/microliters. The sternal marrow showed decrease of megakaryocytes only in 3 out of 18 cases while megakaryocytes in the iliac marrow were reduced in 6 out of 11 cases. Only one of 11 cases showed decrease of megakaryocyte in both marrows examined. On the contrary, four cases showed normal number of megakaryocytes at both sites. Of 9 cases with normal or increased number of megakaryocytes in sternal and/or iliac marrow, no case showed morphologically abnormal megakaryocytes and only one case had the reduced number of platelet-forming megakaryocytes. Results suggested that the number of megakaryocytes in bone marrow especially in the sternum was not reliable for establishing the diagnosis of decreased platelet production, and that about 50% of patients with thrombocytopenia due to hypoproduction of platelets could be diagnosed pertinently only after the study of platelet kinetics.