Stability of salivary steroids: the influences of storage, food and dentalcare

We studied influences of dental care, food and storage on the reproducibili ty of salivary steroid levels. Cortisol (F), 17OH-progesterone (17OHP) and Progesterone (P) were measured using adapted commercial radioimmunoassays. Saliva samples of healthy adults (n = 15; m:8; f:7) were collected directly before and after dental care, and directly before and after breakfast with various foodstuffs. A second experiment investigated stability of steroids under different storage conditions. Four series of identical saliva portio ns (I: Native saliva; II: Centrifuged saliva; III: Saliva with trifluor ace tate (TFA); IV: Saliva with 0.5% NaN3) were stored at room temperature and at 4 degreesC for up to three weeks. To demonstrate influences of repeated thawing and re-freezing of saliva on steroid values, saliva samples (n = 15 ) were divided into identical portions. These portions were frozen and re-t hawed up to 5 times before measurement. Neither dental care nor intake of b read or milk effected the reproducibility of F, 170HP, and P. Steroid level s decreased significantly in the course of three weeks under different stor age conditions (P < 0.001). This decrease was clinically relevant from the second week onward, with exception of NaN3 treated samples. After repeated freezing and re-thawing 17OHP and P decreased slightly (about 5%). Only F d ecreased significantly after the third thawing (P < 0.001). The results sho w the usefulness of standardized handling of saliva samples for improving r eproducibility and reliability of salivary steroid measurements. (C) 2001 E lsevier Science Inc. All rights reserved.