[Total serum iron-binding capacity: problems posed by the use of commercial control sera]

After recalling the conditions of fixation of iron on human native serum, the authors determined the TIBC on 15 commercial control sera after titration. The transferrin concentration was determined on 13 sera of human origin, by two immunochemical techniques. They were thus able to demonstrate certain sera including a chelator substance other than transferrin, their TIBC depends only on the experimental conditions; such sera are not usable for quality control. Lyophilisation seems to reduce the reactivity of sites of fixation. It is thus necessary to provide a large excess of iron and prolong the duration of contact.