The adrenal antibody test is a test that is done for anti adrenal antibodies. Antibodies are created by the body to bind to specific antigens, usually of foreign origin, as part of the regular working of the human immune system. However, due to some kind of mistaken coding or deficiency, the antibodies will end up binding to the normal antigens of the body. Once an antibody binds to an antigen, the pair and whatever the antigen is attached to are marked for destruction by phagocytes. Therefore, anti adrenal antibodies are the body's own immune cells destroying the adrenal glands - the source of nearly all the hormones we require to stay alive. The adrenal antibodies test measures the amount of these antibodies. A destruction of adrenal gland tissue is a condition called Addison's disease and in its most severe case will kill immediately. The test is usually conducted along with tests that measure the effectiveness of adrenocorticotropic hormone and corticotropin releasing hormone to ensure that the negative feedback loop of adrenal cortex-pituitary-hypothalamus axis is not disturbed.
The test is conducted in most cases of autoimmune adrenalitis. This is a condition in which the body's own immune system is trying to destroy the adrenal gland. The antibody test will also comprise of a steroid 21-hydroxlase test to check if the antibodies are specifically destroying that steroid.
There is no specific preparation that you have to do for the test though you will have to refrain from using any kind of corticosteroids like hydrocortisone and prednisone. You might even have to stop take typical antihypertensives like ACE inhibitors losartan and Renin-Angiotesin system disruptors.
The typical antibody test is done which could be an ELISA test or a serology test for the presence of antibodies against the adrenal cortex. The test is quite elaborate. The first test starts with an injection of 250 micrograms of ACTH or corticotrophin. If this results in an increase in cortisol levels by 170 nanomoles per liter and keeps increasing by the hour, the results are normal. If these tests are abnormal, further elaborate time based testing is done to measure the extent of Addison's disease and the ELISA test might be warranted. Dealing with Addison's disease is a matter of being on synthetic glucocorticoid medications for the rest of your life to ensure a normal life. Curiously, the use of synthetic glucocorticoids or corticosteroids in the first place is sometimes the reason for the disease.