Cortisol is a steroid hormone that is produced in the adrenal cortex. The test done to ascertain the levels of this steroid hormone is known as a cortisol level test. The adrenal cortex releases this particular hormone as a response to the ACTH hormone which is secreted by the pituitary gland. The levels of this hormone can help to assess the functioning of the pituitary and the adrenal glands.
To check for cortisol hormone levels, blood is first drawn from a vein in the arm or the hand. After the blood is drawn through an injection, the prick site is cleaned with an antiseptic to prevent infection.
The normal values of the hormone in a healthy adult are 6 to 23 micrograms per deciliter, when taken in the morning. Since the levels of the hormones keep changing throughout the day, the test is done only in the morning, around 8 am.
Abnormal serum cortisol levels or urine cortisol levels can be a cause of various diseases and ailments. If the levels are higher than the prescribed normal levels, it can be an indication of adrenal tumor or ectopic tumors that produce ACTH. Cushing's syndrome is another disease that is caused by increased levels of cortisol in the body.
A decrease in cortisol levels can cause hypopituitarism. Due to a decrease in cortisol levels, Addison's diseases can also be caused. Apart from these, changed levels of cortisol in blood serum or the urine can also cause an acute adrenal crisis.
Though the test is usually accurate, there are several factors that may cause the tests to give an inaccurate result. Physical or emotional stress can temporarily cause a change in the serum cortisol levels. Even though the cortisol levels are normal, they may show as abnormal in the tests. Pregnancy and low sugar in blood also have an effect on the cortisol levels in the blood. Medicines that contain estrogen, cortcosteroids and amphetamines, such as birth control pills, can also cause a temporary change in the cortisol levels of the blood.
To ascertain Cushing's syndrome, a urine test is conducted to check the cortisol levels in the urine. However, there are other tests that can be used to assess the condition of the pituitary and the adrenal glands. ACTH stimulation and dexamethasone suppression tests are usually done if there is a suspicion of Addison's disease.