Multicenter evaluation of assays for estradiol and progesterone in saliva

Blood samples can be difficult to obtain in studies involving serial sampling, especially in developing countries where there may also be logistic, ethical, and cultural constraints that make frequent blood collection impractical. Assays for steroids in saliva may avoid some of these difficulties. A multicenter study involving laboratories in five countries was carried out to compare the results of assays for salivary estradiol and progesterone performed with centrally provided reagents and assay protocols. Concentrations of salivary steroid as obtained by all but one center were comparable with those reported in the literature. We conclude that assays of hormones in saliva are useful adjuncts to those performed on other body fluids.