Multicenter comparison of LC-MS/MS, radioimmunoassay, and ELISA for assessment of salivary progesterone and estradiol

Our findings suggest that while LC-MS/MS, RIA, and ELISA were capable of meeting most of the specified criteria for P4, only LC-MS/MS and RIA were able to perform similarly sufficiently at low E2 levels. LC-MS/MS provided more accurate and reliable measurements for P4 and E2, especially at low concentrations, but encountered challenges, too. Although RIA showed comparable performance to LC-MS/MS, it still suffered partly from cross-reactivity. ELISA often overestimated hormone levels and exhibited greater divergence. These differences highlight the importance of carefully selecting methods and considering their limitations in research applications.