Clinical Chemistry, Vol 17, 941-947, Copyright © 1971 by the American Association for Clinical Chemistry

Use of an Anion-Exchange Column to Determine Serum Iron-Binding Capacity

¹ Departments of Biochemistry and Laboratory Medicine, University of Washington School of Medicine, Seattle, Wash. 98105.

A rapid procedure is described for determining total iron-binding capacity (TIBC) by use of a small, disposable resin column. Serum is saturated with excess ferric citrate, and iron not bound to protein is then removed by passing the mixture through the column of anion-exchanger. Transferrin-bound iron in the effluent, the TIBC, is determined colorimetrically (AutoAnalyzer), with 2,4,6-tripyridyl-1,3,5-triazine as color reagent. The percentage saturation with iron may be obtained from colorimetric measurement of original serum iron and the TIBC, or by radioactive counting if ⁵⁹Fe is incorporated in the ferric citrate used to saturate the serum. Our method is compared with the MgCO₃ precipitation technique for the removal of excess iron after saturation and to an ultrafiltration technique in which protein-bound iron is retained by a membrane and the filtrate analyzed for unbound iron, thus obviating absorbents in the determination of TIBC. Results from the resin-column and ultrafiltration procedures correlated well, whereas those from the MgCO₃ method were consistently lower and more erratic.

Submitted on February 24, 1971
Accepted on May 31, 1971