Factors affecting the serum iron-binding capacity in the elderly.

The relationship of the serum iron-binding capacity (IBC) to the serum proteins and other haematological parameters was studied in 96 elderly subjects. With two exceptions, IBC levels above the normal range were confined to cases of anaemia with transferrin saturation levels of less than 12%. In 13 cases the IBC was below normal, and in 9 it was normal in the presence of iron deficiency; in these groups the IBC correlated with serum albumin, and there was a clinical explanation for protein depletion. In cases with normal serum albumin and normal transferrin saturation, there was no decline in IBC with age. The best serological index of iron status was the transferrin saturation, which was less than 12% in significant iron deficiency. Malabsorption of inorganic iron was demonstrated in 11 out of 30 iron-deficient patients, 4 of whom had reduced IBC, but there was no relationship between iron absorption and the IBC.