Estrogen radioimmunoassay suitable for the monitoring of ovulation induction.

A rapid radioimmunoassay for estrogen in serum was characterized and validated. Analytical recoveries of estrone and estradiol were essentially 100%; estriol was not measured because it was eliminated by sample-handling procedures. Nonspecific interference from serum extracts, which was initially reflected by positive blanks, was eliminated by a sodium hydroxide wash of the extract. Validation of the procedure included determination of a reference interval for estrogen that agreed with the sum of estradiol and estrone concentrations reported in the literature for eugonadal women. Clinical applicability of the assay was demonstrated by monitoring estrogen concentrations during the menstrual cycle and during urogonadotropin (Pergonal)-induced follicular maturation. Because of its rapid turnaround time, the assay is ideally suited for monitoring the frequency with which urogonadotropin should be administered to the infertile patient, and the dosage, thus decreasing the likelihood of multiple pregnancies or ovarian hyperstimulation.