Thrombopoietin Activity in Idiopathic Thrombocytopenic Purpura

In this study we have attempted to measure thrombopoietic activity in patients with idiopathic thrombocytopenic purpura. The activity was more readily detectable in serum than in urine. When a high level of thrombopoietic activity was found, it was often followed within a few days by a rise in platelet count. Activity was significantly elevated only in acute and recurrent ITP, although a suggestive increase was found in chronic ITP. Patients with iron deficiency had no thrombopoietic activity in this assay, even though many of them had elevated platelet counts.