Cortisol, Serum (Morning Sample)

A cortisol test is done to measure the level of the hormone cortisol, a primary stress hormone which provides protective response to a perceived threat or danger. There are certain diseases, such as Addison’s disease and Cushing’s disease, which may affect the production of cortisol in the body.
This test is done to diagnose Cushing’s syndrome, Addison’s disease and to check the functioning of the adrenal gland.
The level of cortisol hormone rises and falls during the course of a day. These levels are highest in the early morning, drop slowly throughout the day reaching the lowest around midnight. Usually, the test involves drawing blood in the morning before 10 AM.