By determining the percentage utilization of intravenously administered radioiron for hemoglobin production over a period of two to three weeks, certain measurements of internal iron metabolism can be made.
With a normal rate of blood production, changes in per cent utilization reflect alteration in iron stores. Iron depletion is characterized by more rapid and more complete utilization of radioiron. States of iron excess in hemochromatosis can be identified by their profound depression of radioiron utilization.
If, on the other hand, storage iron is not greatly altered, the percentage utilization is determined by the function of the erythropoietic tissue. In myelophthisic anemias, in uremia, and in infection, a similar depression of the curve is found.
The rate of erythropoiesis may further be estimated by the slope of the utilization curve, and evidence of abnormal red cell destruction is found in early and abrupt plateau of the utilization curve.
A correlation has been made in a variety of hematologic disorders between the radioiron utilization for hemoglobin production and the clinical factors which might be expected to affect iron metabolism in these patients.