Iron absorption. Measurement of ingested iron59 by a human whole-body liquid scintillation counter.

The availability of radioactive isotopes of iron led to the development of reliable methods of studying iron kinetics (1), but the absorption of iron by the gastrointestinal tract was still determined indirectly by the amount of unabsorbed iron excreted in the stools or by quantification of isotopic iron incorporated into hemoglobin (2-7). The availability of a whole-body counter in a clinical facility has made possible the direct assay of iron59 retention in human subjects and has eliminated sample collecting and preparation. The purpose of this paper is to describe this method and demonstrate some of the findings.