The ACTH stimulation test is used to measure how well the adrenal glands are working. The ACTH stimulation test is used to diagnose Cushing’s disease or Addison’s disease.
Cushing’s disease results in the excessive production and release of the cortisol, also described as "hyperadrenocorticism". Addison’s disease, or "hypoadrenocorticism", is caused when the adrenal glands produce too little cortisol.
The ACTH stimulation test involves injecting a small amount of ACTH (adrenocorticotropic hormone), and then taking a blood sample to measure cortisol levels.