Evaluation of an enzyme-immuno-assay for the determination of total serum estrogens in pregnancy.

We have evaluated a new diagnostic kit for the determination of total estrogens in serum or plasma of pregnant women by means of an enzyme-immuno-assay. Within-run precision had a coefficient of variation of 4.7-4.9% for total estrogen concentrations of 400 to 2000 nmol/l. For the same range of concentrations, day-to-day precision was found to be 5.9-8.9%. Mean analytic recovery of unconjugated estriol was 102%. Enzymatic hydrolysis of different estrogen conjugates was shown to be virtually complete. The antiserum used in the assay has the same affinity for estrone, estradiol and estriol. Preliminary clinical studies included 14 pregnant women. The results suggest that the determination of total estrogens in pregnancy plasma can be used to monitor fetoplacental function in much the same way as urine total estrogens are used.