Serum Testosterone in Women as Measured by an Automated Immunoassay and a RIA

Taieb et al. (1) in their recent report in Clinical Chemistry described the relationship of serum testosterone concentrations measured by 10 immunoassays and by isotope-dilution gas chromatography–mass spectrometry (ID/GC-MS). Automated immunoassays fared badly, but RIAs agreed well with the ID/GC-MS.In contrast to our findings, Taieb et al. (1) reported, in women, increased serum testosterone as assayed in the AutoDelfia immunoassay system (Perkin-Elmer). Between November 1, 2002, and February 28, 2003, we found for 2057 women a mean (median) testosterone of 2.1 (1.6) nmol/L by AutoDelfia, similar to the values of 1.7 (1.4) nmol/L for 2180 different female samples assayed consecutively in our routine using the Orion Diagnostica RIA between November 1, 2001, and February 28, 2002. By contrast, Taieb et al. (1) reported mean concentrations of ∼5 nmol/L in the female samples measured by the AutoDelfia.In the same time periods, consecutive male samples had mean (median) values of 16.7 (14.8) nmol/L by AutoDelfia (n = 1447) and 13.9 (12.9) nmol/L by the Orion (n = 1505). Again, the difference between the automated … [↵][1]aAuthor for correspondence. Fax 33-1-4249-4280; e-mail philippe.boudou{at}sls.ap-hop-paris.fr. [1]: #xref-corresp-2-1