Testosterone Measured by 10 Immunoassays and by Isotope-Dilution Gas Chromatography-Mass Spectrometry in Sera from 116 Men, Women, and Children

• Published in: Clinical chemistry (Baltimore, Md.) Vol. 49; no. 8; pp. 1381 - 1395
• Main Authors: Taieb, Joelle, Mathian, Bruno, Millot, Francoise, Patricot, Marie-Claude, Mathieu, Elisabeth, Queyrel, Nicole, Lacroix, Isabelle, Somma-Delpero, Claude, Boudou, Philippe
• Format: Journal Article
• Language: English
• Published: Washington, DC Am Assoc Clin Chem 01-08-2003; American Association for Clinical Chemistry; Oxford University Press
• Subjects: Adult; Aged; Autoanalysis - methods; Biological and medical sciences; Child; Endocrinology; Female; Gas chromatography; Gas Chromatography-Mass Spectrometry; Humans; Immunoassay - methods; Immunoassays; Investigative techniques, diagnostic techniques (general aspects); Male; Mass spectrometry; Medical sciences; Middle Aged; Pathology. Cytology. Biochemistry. Spectrometry. Miscellaneous investigative techniques; Radioisotope Dilution Technique; Testosterone - blood; Human; Androgen; Isotope dilution; Male; Immunological method; Gas chromatography; Testosterone; Measurement technique; Clinical biology; Female; Serum; Reliability; Child; Mass spectrometry
• ISSN: 0009-9147; 1530-8561
• DOI: 10.1373/49.8.1381

Commercially available testosterone immunoassays give divergent results, especially at the low concentrations seen in women. We compared immunoassays and a nonimmunochemical method that could quantify low testosterone concentrations.
We measured serum testosterone in 50 men, 55 women, and 11 children with use of eight nonisotopic immunoassays, two isotopic immunoassays, and isotope-dilution gas chromatography-mass spectrometry (ID/GC-MS).
Compared with ID/GC-MS, 7 of the 10 immunoassays tested overestimated testosterone concentrations in samples from women; mean immunoassay results were 46% above those obtained by ID/GC-MS. The immunoassays underestimated testosterone concentrations in samples from men, giving mean results 12% below those obtained by ID/GC-MS. In women, at concentrations of 0.6-7.2 nmol/L, 3 of the 10 immunoassays gave positive mean differences >2.0 nmol/L (range, -0.7 to 3.3 nmol/L) compared with ID/GC-MS; in men at concentrations of 8.2-58 nmol/L, 3 of the 10 immunoassays tested gave mean differences >4.0 nmol/L (range, -4.8 to 2.6 nmol/L).
None of the immunoassays tested was sufficiently reliable for the investigation of sera from children and women, in whom very low (0.17 nmol/L) and low (<1.7 nmol/L) testosterone concentrations are expected.