title: Development of a direct [125I]radioimmunoassay for serum levels of 17-hydroxyprogesterone.
abstract: We describe a direct, rapid, sensitive and highly specific radioimmunoassay for determining serum levels of 17-hydroxyprogesterone. It is based on the use of highly specific sheep antiserum, 125I-labelled tracer, dextran-coated charcoal to separate the antibody bound and free fractions, and sodium salicylate to eliminate interference from endogenous binding proteins in serum. Intra- and interassay coefficients of variation are less than 8% and recovery is satisfactory. Sensitivity is 3.5 fmol per assay tube (0.14 nmol/l). Results correlate closely with those of an established technique using 3H-labelled steroid after initial solvent extraction and column chromatography of samples (y = 1.02x - 0.16; r = 0.998). The values found for serum from normal adult subjects ranged from 1.0 to 12.1 nmol/l while those from treated and untreated patients with congenital adrenal hyperplasia due to 21-hydroxylase deficiency were 1.4-18.4 and 27.3-650 nmol/l, respectively.
authors.affiliation: Department of Chemical Pathology, St Bartholomew's Hospital, London, England, UK.
authors.forename: B A
authors.initials: BA
authors.lastname: el-Gamal
authors.forename: L A
authors.initials: LA
authors.lastname: Perry
authors.forename: J
authors.initials: J
authors.lastname: Landon
mesh_terms: D019326:17-alpha-Hydroxyprogesterone; D000312:Adrenal Hyperplasia, Congenital / Q000097:blood; D006801:Humans; D006908:Hydroxyprogesterones / Q000097:blood*; D007106:Immune Sera; D011485:Protein Binding; D011863:Radioimmunoassay / Q000379:methods*; D012980:Sodium Salicylate / Q000494:pharmacology
chemical_list: D006908:Hydroxyprogesterones; D007106:Immune Sera; D019326:17-alpha-Hydroxyprogesterone; D012980:Sodium Salicylate