Serum and Salivary Cortisol Assessment in Patients With Adrenal Incidentalomas and Healthy Controls

The goal of this observational study is to evaluate the diagnostic accuracy of salivary cortisol compared with serum cortisol after a 1 mg overnight dexamethasone suppression test in participants (N = 100) with adrenal incidentalomas and healthy control participants (N = 100). The main question it aims to answer is: Are salivary cortisol and serum cortisol equal diagnostic tools for endogenous hypercortisolism? The inclusion of healthy controls will serve as a reference population to define the central 95 % reference interval for the serum and salivary cortisol levels. Participants will undergo routine medical examination of adrenal incidentalomas including 1 mg dexamethasone-suppression-test, 24 h urine sample, and measurement of plasma-adrenocorticotropin (ACTH). In addition to the routine biochemical tests, saliva samples will be collected the morning and evening before intake of dexamethasone as well as the following morning together with serum cortisol.