The Metabolism of Intravenously Administered Iron‐Dextran

S ummary . A method is described for the separation of transferrin iron and iron‐dextran in plasma samples. Estimation of plasma levels following the intravenous administration of labelled iron‐dextran showed that the mean half clearance time was 5.9 hr. About 40% of the injected dose of iron in circulation was bound to transferrin 11 hr later and there was no difference between normal and iron deficient subjects in the rate of iron release by the reticuloendothelial system. The results indicate a need to re‐evaluate present concepts of reticuloendothelial iron metabolism.