ACTH Suppression Test

Sample: Serum sample 8 hrs after dexamethasone adninistration

Range: Cortisol (a.m.) levels drop to very low values in healthy individuals

Remarks:  Administration of Dexamethasone (a synthetic glucocorticoid that is 64 times more potent than cortisol) suppresses the release of ACTH by negative feedback in patients with a normal hypothalamic-pituitary-adrenal axis (Cushings disease). As a result, the cortisol (a.m.) levels decrease to very low levels in healthy individuals. Patients with hypercortisolism lose normal negative feedback control and they have higher cortisol (a.m.) levels after dexamethasone administration.


Available tests