On the processing of saliva samples for progesterone assay

Reports from several laboratories indicate that the concentration of progesterone in the saliva provides a valid indicator of corpus luteum function. However, optimal conditions for the treatment and storage of saliva specimens prior to analysis was not addressed in these papers. We have found that 1) sonication of saliva in brief bursts produces a homogeneous sample from which progesterone is removed quantitatively by a single extraction with hexane in a vortex mixer, and 2) prompt freezing of saliva is important since storage of samples at room temperature for 48 hours results in a significant decrease in radioimmunoassayable progesterone. Four normal women provided daily saliva specimens throughout one menstrual cycle and serum samples every 3 days during the luteal phase. Excellent correlations between the progesterone profiles in the two fluids were obtained.