Cortisol tests are blood tests done to measure the quantity of cortisol in the blood. It also is carried out to check if the adrenal glands or pituitary glands are producing the required levels of hormones. Cortisol is a hormone that is made by the adrenal glands. The levels of cortisol in the body go up, if the pituitary glands release too much of a hormone called ACTH (adrenocorticotropic hormone).
Importance of cortisol: Cortisol helps the body to metabolize fat and sugar (glucose) and convert it to energy. It also helps the body to manage stress. Our cortisol levels are usually highest in the early morning hours and lowest in the evening, just before we go to sleep. Cortisol levels could be affected by emotional or physical stress, injury, infection, strenuous activity or if your normal daily rhythm is upset. This may lead to over-active adrenal glands.
To find out the cortisol test levels, blood samples will be taken twice - in the morning and again in the afternoon.
How it is done: In a cortisone test, blood will be drawn from a vein in your inner elbow, after cleaning the site with antiseptic. You may feel a slight prick or sting when the needle goes in, and there may be a slight bruise for a few days. Besides this, there are very few risks involved in a test to determine cortisone test levels.
Before the test: You may have to take a few precautions before the test in order not to affect the cortisone test levels. You will have to avoid strenuous activities 24 hours prior to the test. You may also have to rest and lie down for half an hour before the test. Speak to your doctor about any medications you are taking. Avoid any other test involving a radioactive scan, at least a week before the test. In case you are taking certain medicines like steroids, your doctor would probably ask you to stop taking them a day before, since they affect the accuracy of the cortisone test results.
What can affect the results: Certain factors are known to affect the cortisone test levels and give a false picture. For example, being pregnant or being under emotional or physical stress may cause your cortisone levels to be higher than usual. Exercising, eating or drinking immediately before the test, hypoglycemia (low blood sugar) or taking medicines like amphetamines, corticosteroids, birth control pills or hormone supplements of estrogen may also give inaccurately high cortisone test results.
Test results: Low levels of cortisol may be an indication of Addison's disease or Sheehan's syndrome, while high levels may indicate Cushing's disease.