Comparison of 8 different colorimetric, radiochemical and immunological procedures for the determination of iron binding capacity.

Two radiochemical (Irosorb 59 and Res-O-Mat Fc), a mechanized (DSA 560) and several manual colorimetric procedures (test combination of Roche, Merck and Haury) for the determination of the total iron binding capacity were compared with the transferrin-binding capacity (immunoprecipitation). Whereas all methods show a satisfactory correlation with the transferrin concentration, most colorimetric procedures lead to higher values, while the Merckotcst leads to lower values for the total iron binding capacity. In some control sera the total iron binding capacity is overestimated by several colorimetric methods, which are also subject to interference by hemoglobin. All other procedures are unaffected by hemolysis. With the mechanization of procedures for immunoprecipitation, these methods are now to be preferred.