ACTH Blood Test (Adrenocorticotropic Hormone)

The ACTH blood test measures the level of adrenocorticotropic hormone, a pituitary hormone that controls cortisol production by the adrenal glands. It is used to investigate secondary hypertension, particularly when a hormonal cause such as Cushing's syndrome or primary aldosteronism is suspected. It is also valuable in the work-up of adrenal insufficiency and in monitoring patients with known pituitary or adrenal disease.

ACTH is measured using a sensitive immunometric assay, providing a reliable assessment of the hypothalamic-pituitary-adrenal (HPA) axis. Because ACTH secretion follows a diurnal rhythm, the timing of the sample can influence results, and your clinician will interpret the finding alongside cortisol levels and your clinical picture.

Biomarkers included

Pituitary Hormones
- Adrenocorticotropic hormone (ACTH)

Why it matters
ACTH is the key regulator of cortisol production. An abnormal result can reveal whether hypertension or other symptoms are driven by an overactive or underactive adrenal axis, guiding targeted treatment and preventing the long-term cardiovascular and metabolic consequences of undiagnosed hormonal disease.