Estriol radioimmunoassay in plasma and urine

A specific radioimmunoassay of estriol has been developed using an antiserum obtained by immunization of rabbits against 1,3,5 (10)-Estratrien -3, 16 alpha 17 beta-triol-6 one 6 carboximethyl oxime: BAS (Estriol 6-CMO-BSA). The tracer used was Estriol (2, 4, 6, 4, 3H (N)). This assay does not require prior hydrolysis, extraction or purification. Either plasma, serum or urine can be used. Urine only requires 100 microliter (1:5) dilution and 100 microliter in serum or plasma. An incubation time of 60 minutes is requires; a linear standard curve is obtained by logit-log extrapolation and a good correlation was obtained (r = 0.063) with estriol determination by comparison to a generally accepted colorimetric method. The detection range is from 100 pg to 50,000 pg in plasma or serum and urine. The specificity of the antibody was determined by studies of cross reactivity with other steroids. The sensitivity (100 pg) and accuracy were proven to be highly satisfactory. This method is simple, rapid and accurate.