Evening ACTH Hormone Test - Adrenocorticotropic Hormone (ACTH) Test, Evening

The adrenocorticotropic hormone (ACTH) level is measured in blood plasma during the evening or midnight (usually between 10 PM and midnight), when its natural secretion is at its lowest. This is primarily used as part of the dynamic assessment for the diagnosis of Cushing's syndrome (hypercortisolism), in which the normal circadian rhythm is disrupted, and ACTH (and cortisol) levels remain elevated at night.