Method for Determining Iron-Binding Capacity of Serum.

A simple radioisotopic method is described for determining the iron-binding capacity of serum. 2. In principle, iron labelled with a radioactive tracer is added to a serum sample in excess of the binding capacity, and that which becomes attached is separated by protein precipitation and measured isotopically. 3. The method was evaluated by measurement of: (a) the recovery of radioiron added in increments to serum samples, (b) the amount of iron exchanged between the saturated iron proteinate and the excess iron in solution, and (c) the difference in residual binding capacities from the original value after the addition of increments of nonradioactive Fe ascorbate to serum samples.