Erythrokinetics. IV. The plasma iron turnover as a measure of erythropoiesis

Experimental and clinical studies have been performed to define more clearly the significance of the plasma iron turnover. It has been shown that the plasma iron turnover is not affected by the rate of red cell destruction and to only a limited extent by increased body stores. It does, however, reflect the degree of erythroid marrow activity and is a sensitive indicator for measuring changes in such activity. A series of 85 studies in normal subjects and in patients with various hematologic disorders were carried out to define the range of response with anemia and to assess the clinical value of the plasma iron turnover as an index of erythropoiesis. In states of marrow hyperfunction it is increased from 3 to 6 times normal and may be depressed to approximately half normal with marrow hypofunction. The plasma iron turnover is increased with marrow dyspoiesis. This increase is a measure of total erythropoiesis and does not indicate the production of viable red cells.