Comparison of dextran-coated charcoal and ammonium sulfate in the radioimmunoassay of estrogens.

A comparison was made between the use of ammonium sulfate (AS) and Dextran coated charcoal (DCC) to separate free and antibody-bound estrogens in the RIA of estrone and estradiol in serum. Under the conditions tested, AS yielded values which were approximately twice those obtained using DCC. This difference was found for both estrogens, using male and female serum and regardless of whether the estrogens were separated from one another by means of the Girard reagent or TLC. There was no significant difference in the sensitivity, accuracy or usable range of the standard curve or in the water-blank for the two procedures.