Studies of Plasma Fe⁵⁹ Disappearance—A Manifestation of Ineffective Erythropoiesis and of Hemolysis

1. Studies of the plasma radioiron disappearance data have revealed a relative "elevation" of plasma radioactivity after the second day in normal subjects, and after the first day in patients with hemolytic anemia, megaloblastic anemia and thalassemia. This elevation in plasma radioactivity in normal subjects may be interpreted as due to the return to plasma of radioiron from those cells that are "ineffectively" produced and are hemolyzed in the marrow. Other interpretations are also presented.

2. Dyspoieses involving ineffective red cell economy, but not detectably affecting iron economy are contrasted with disorders involving ineffective utilization of iron and of pigment alone.

3. After the first day plasma radioiron activity shows a diurnal variation similar to the diurnal variation in plasma iron concentration.