Testosterone measured by 10 immunoassays and by isotope-dilution gas chromatography-mass spectrometry in sera from 116 men, women, and children.

Background: 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.

Methods: 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).

Comparison of progesterone concentration determination by 12 non-isotopic immunoassays and gas chromatography/mass spectrometry in 99 human serum samples.

A single serum progesterone determination may be highly predictive for early pregnancy and in vitro fertilisation and embryo-transfer outcomes. We therefore compared 12 direct non-isotopic progesterone immunoassays with gas-chromatography/mass spectrometry (GC/MS). For each assay, data from the analysis of 99 individual sera were compared with data obtained by GC/MS, using regression and bias plot analyses and the ratio method.

[Validity of immunochemical methods for bloody progesterone: a study performed in 1998].

The aim of this study was to compare, with manufacturer's agreement, twelve direct and non-isotopic commercial assays of progesterone. We have evaluated the analytical performances: low limit detection, imprecision, accuracy (recovery and dilution tests) and we have tested some patient samples. Results were compared to a reference method using isotope dilution Gas Chromatography and Mass Spectrometry combination (GC-MS).