Suitability of saliva stimulants for valid assessment of steroid hormones via radioimmunoassay.

Salivary steroid measurement is a popular way to assess endocrine hormone levels, but efficient sample collection can be challenging because the use of stimulants can interfere with valid measurement. The aim of this study was therefore to identify a stimulant that can be used in assessment of the steroid hormones cortisol (C), testosterone (T), progesterone (P) and estradiol (E2) without impairing their quantification by radioimmunoassay. Study 1 and 2 explored the suitability of potential stimulants in comparison to unstimulated saliva collection. Study 3 tested stimulants under standardized conditions in water. Across all three studies, Parafilm® wax foil performed best and was therefore tested once more and validated as a saliva stimulant in Study 4. No significant differences between unstimulated saliva and Parafilm®-stimulated saliva could be found for any of the four hormones assayed. Therefore, Parafilm® appears to be a suitable saliva flow stimulant for assaying the salivary steroid hormones C, T, P and E2 by radioimmunoassay.