Immunoassays for Testosterone in Women: Better than a Guess?

Recent developments in the field of mass spectrometry have provided the accuracy and sensitivity to evaluate very-low-abundance steroids such as testosterone in fe-male and pediatric patients. In this issue of Clinical Chemistry, Taieb et al. (1) present the most comprehensive evaluation of automated testosterone immunoassays to date. They compared 10 commercially available immuno-assays with isotope-dilution gas chromatography–mass spectrometry (ID-GC/MS) and reached the inescapable conclusion that testosterone immunoassay results for specimens from females are inaccurate. Similar data have been reported for individual testosterone immunoassays previously (2), but Taieb et al. (1) are the first to show that for every commercially available testosterone assay stud-ied, the values are in error—by a factor of 2 on averag