ABSTRACT
We report a reliable radioimmunoassay for plasma progesterone in which polyethylene glycol ("Carbowax 6000") is used to separate antibody-bound and free hormone. Initially, progesterone is concentrated by putting the sample through a column of LH-20 Sephadex. Procedural losses in each sample are not monitored. We compared the reliability and practicality of this method with that of another method in which procedural losses are monitored for each sample; accuracy and precision were similar. Our method saves technical assay time and scintillation counter space and time without sacrificing reliability.
Subject(s)
Progesterone/blood , Chromatography, Gel , Cross Reactions , Evaluation Studies as Topic , Humans , Polyethylene Glycols , Radioimmunoassay/methods , Time FactorsABSTRACT
A rapid, non-chromatographic radioimmunossaay for unconjugated estriol in pregnancy plasma has been developed which utilizes a commonly available antiestrogen antisera. Estradiol-17beta and estrone demonstrate 135% relative cross-reactivity with our antiserum, as compared with 100% for estriol. Specificity is achieved by purification of estriol with solvent partitioning using benzene: petroleum ether (1:1). The results obtained using this method are similar to a radioimmunoassay utilizing a highly specific, but commercially unavailable, antiestriol antiserum. The method is precise, with coefficients of variation ranging from 3.0 to 8.2%.
Subject(s)
Estriol/blood , Antibody Specificity , Estriol/isolation & purification , Estrogens , Female , Humans , Pregnancy , RadioimmunoassayABSTRACT
We describe a rapid, reliable radioimmunoassay for unconjugated estriol in plasma. Polyethylene glycol (Carbowax 6000) is used to separate antibody-bound and free steroid. The assay is sensitive (25 pg for standards), precise, and accurate. At high and low concentrations of estriol, intra-assay coefficients of variation were 7.1% and 7.6%, respectively, and inter-assay coefficients of variation were 7.2% and 10.0 %, respectively. Free [3H] estriol is not precipitated by polyethylene glycol. This radioimmunoassay of estriol, with a highly specific antiserum and with polyethylene glycol as the antibody precipitant, is a reliable one-day assay that is practical both for the clinical laboratory and the obstetrician.
