Blood contamination and the measurement of salivary progesterone and estradiol.

The impact of blood leakage due to microinjury to the oral cavity on the measurement of salivary reproductive hormones was examined. Saliva samples were collected before, immediately after, and then every 15 min for 1 h following vigorous tooth brushing. Blood in saliva was quantified by visual inspection of discoloration and an immunoassay for transferrin. Levels of progesterone increased, and levels of estradiol decreased, in saliva after microinjury. These changes were present only immediately after microinjury. The findings have implications for the use of salivary assays in biobehavioral research, short-term dynamic investigations, pharmacokinetic analyses, and studies of chronobiological changes in progesterone and estradiol levels.