Use of salivary cortisol and cortisone in the high- and low-dose synacthen test

Context Salivary cortisone reflects serum cortisol levels, is more sensitive than salivary cortisol at lower values of serum cortisol and is non-invasive. Objective To investigate the relationship between serum cortisol and salivary cortisol and cortisone following low and high-dose synacthen. Design and Setting Prospective pharmacodynamic studies in clinical research facilities. Participants and Intervention 35 dexamethasone-suppressed, healthy adult males underwent an intravenous synacthen test: N=23 low-dose (1mcg), N=12 high-dose (250mcg). Paired serum and salivary samples were taken at 15 sampling points over 120 minutes. Main outcome measure Serum cortisol and salivary cortisol and cortisone were analyzed for correlations and by a mixed effects model. Results At baseline the correlation between serum cortisol and salivary cortisol was weak with many samples undetectable (r=0.45, NS), but there was a strong correlation with salivary cortisone (r=0.94, p