Individual test · Labcorp 004440

Adrenocorticotropic Hormone (ACTH), Plasma

This test measures the amount of adrenocorticotropic hormone (ACTH) in your blood, a chemical messenger made by the pituitary gland that signals your adrenal glands to produce cortisol. It helps identify the cause of symptoms related to too much or too little cortisol, such as severe fatigue, muscle weakness, or unexplained weight changes. By checking these levels, the test helps distinguish between issues originating in the pituitary gland versus the adrenal glands. However, since ACTH levels fluctuate naturally throughout the day, this test alone cannot provide a final diagnosis and is often evaluated alongside other hormone tests.