- ACTH (adrenocorticotropic hormone)secreted by the anterior pituitary in response to corticotrophin-releasing hormone CRH from the hypothalamus as well as in response to stress.
- ACTH stimulates the secretion of steroids including Cortisol from the adrenal cortex.
- This peptide hormone undergoes diurnal variation and samples are usually collected early morning.
- ACTH is used in the investigation of Cushing's syndrome, and in differentiating primary from secondary causes of adrenal insufficiency.
- An isolated ACTH level is rarely diagnostically useful as levels should be interpreted in the context of the current cortisol concentration so samples for ACTH must normally be sent with a serum sample for cortisol collected at the same time.
- Adults, blood taken into a 4mL EDTA tube sent immediately to the laboratory on ICE
- Send a simultaneous tube for cortisol.