Adrenocorticotropic hormone (ACTH) level

Adrenocorticotropic hormone (ACTH) levels, measured in picograms per milliliter (pg/mL), typically range between 10 and 60 pg/mL in the early morning, and ACTH testing helps assess adrenal gland and pituitary gland function. 

ACTH levels often are elevated to higher than 250 pg/mL in patients with Addison disease. However, ACTH is unstable in plasma, and specimen collection and storage may require special attention. The specimen should be collected in iced anticoagulated plastic containers and frozen immediately.

High ACTH and high cortisol levels are a sign of pituitary tumor that makes ACTH (Cushing's disease). The extra ACTH triggers your adrenal glands to make too much cortisol. You'll likely need more tests, such as a CT or MRI scan, to confirm whether you have a pituitary tumor.