Simple assay of estrogen in urine during pregnancy by means of latex agglutination inhibition reaction.

A simple and rapid method, latex agglutination inhibition reaction (LAIR), using anti-estriol-16-glucuronide coupled with BSA for estimating estrogen in urine has been developed. Agglutination of the latex reagent by the antiserum occurs within 3 min. The agglutination, however, was completely inhibited by 100 ng/ml or more of estriol. There was a good correlation in results obtained by LAIR and by colorimetry, RIA and GLC. Urine samples (3329) obtained at various gestational weeks were assayed. The samples from 94% of the normal pregnant patients in the third trimester revealed 10 micrograms/ml or more of estrogens. Although the assay is semiquantitative, it may be useful in screening for fetal well-being in high-risk pregnancies.