A Method for the Rapid Colorimetric Assay of Total Estrins in Pregnancy Urine1

Publisher Website
Google Scholar
Abstract
A rapid method of assaying the total estrin content of pregnancy urine is presented in which a Kober-Ittrich color reaction is applied to a simply purified unhydrolyzed urinary residue. Purification is effected by quantitative precipitation of the urinary estrins with 70% (w/v) (NH4)2SO4. Assay values obtained for solutions of these precipitates averaged 20% higher than those obtained by a standard Brown technique for normal urines, and 44% higher for a group of urines from abnormal pregnancies. These differences are believed to be due primarily to the assay of estrins in the precipitate which are destroyed by the Brown method. The new method is compared with and found superior to 2 other methods directly applying the Ittrich color test (a) to urine, and (b) to a gel filtrate of the conjugated estrins of pregnancy urine. The (NH4)2SO4 method is simple and requires no special apparatus or procedure. Pregnancy urines containing more than 1 mg estrin/day can be assayed and 1-6 assays can be completed in 4-5 hr. This test may readily be used In the rapid determination of fetal well-being.