title: Assay of plasma testosterone during the first six months of life: importance of chromatographic purification of steroids.
abstract: Determination of the plasma concentration of testosterone (T) is important in evaluating infants born with ambiguous genitalia and micropenis, and several commercially available kits provide a direct assay of T in unextracted plasma. Using plasma samples obtained from 36 subjects < 6 months old, we compared the concentration of plasma T measured by RIA after extraction and purification by column chromatography with the T concentration measured in a direct assay. When aliquots of samples were purified before RIA, the concentration of T was markedly lower than in the direct assay. In the first 3 weeks postpartum, results of the direct assay were 3.8-fold greater than those obtained after purification. This difference decreased over time, and by age 2 months there was fairly good agreement between the two methods. These data indicate that some direct assays of plasma T are inappropriate during the first 2 months postpartum.
authors.affiliation: Division of Pediatric Endocrinology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA.
authors.forename: J S
authors.initials: JS
authors.lastname: Fuqua
authors.forename: E S
authors.initials: ES
authors.lastname: Sher
authors.forename: C J
authors.initials: CJ
authors.lastname: Migeon
authors.forename: G D
authors.initials: GD
authors.lastname: Berkovitz
mesh_terms: D002251:Carbon Tetrachloride; D002845:Chromatography; D012734:Disorders of Sex Development / Q000097:blood*; D005260:Female; D005783:Gender Identity; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D011863:Radioimmunoassay; D013739:Testosterone / Q000097:blood*
chemical_list: D013739:Testosterone; D002251:Carbon Tetrachloride