Reproducibility of Nighttime Salivary Cortisol and Its Use in the Diagnosis of Hypercortisolism Compared with Urinary Free Cortisol and Overnight Dexamethasone Suppression Test

Abstract

Based on its remarkable reproducibility, easy noninvasive nature, and at least similar diagnostic performance, NSC appears to be a preferable alternative to 24-h UFC as a first-line screening test for CS. The cutoff values of NSC, 24-h UFC, and urinary cortisol/creatinine ratio have to be carefully adjusted using assay and center-specific reference ranges of sufficiently large populations.