The adrenal glands are located on top of the kidneys and play a prime role in the body's endocrine system. The endocrine system uses special chemicals called hormones to help regulate many important processes in the body. Conditions such as Addison's disease and Cushing's disease both involve the adrenal glands. In general, adrenal function is assessed through blood tests.
Cortisol Test
Cortisol is a hormone produced by the adrenal glands, and its chief role is to modulate the body's response to stress (both physical and emotional). Lab Tests Online notes that cortisol levels are commonly measured to assess the body's adrenal function. Because cortisol levels in part reflect the body's circadian rhythm (highest in the morning just after wakening and lowest at night), multiple measurements may need to be taken. Abnormally low or high cortisol levels can be a sign of problems with the adrenal glands. The test may be done with a blood sample, though urine and saliva samples can also be used.
Aldosterone
Aldosterone is another test that can be used to diagnose adrenal problems. Aldosterone, which is also produced by the adrenal glands, helps the body regulate its electrolyte balance. Aldosterone is typically measured with a blood or urine sample. Low aldosterone levels can indicate adrenal insufficiency or adrenal failure.
ACTH Stimulation
If a cortisol test shows that overall cortisol levels are low, it can indicate a problem with the adrenal glands or with the pituitary. As the National Institute of Diabetes and Digestion and Kidney Disorders (NIDDK) explains, the pituitary secretes a hormone called adrenocorticotropin hormone (ACTH), which stimulates the adrenal glands to produce more cortisol. Patients receiving an ACTH stimulation test have their cortisol levels measured before and after administration of synthetic ACTH. If cortisol levels are unable to sufficiently rise, it suggests that there is a problem with the adrenal glands.
Dexamethasone Suppression
Medline notes that a dexamethasone suppression test can be used to determine the cause of abnormally high cortisol levels. With this test, a patient's cortisol levels are measured before and after they are given a drug called dexamethasone, which is a synthetic corticosteroid. This drug normally causes the adrenal glands to produce less cortisol. If cortisol levels continue to be high after administration of dexamethasone, it suggests an abnormality within the adrenal gland is causing excessive cortisol production.
