Cortisol is a steroid hormone produced in the adrenal cortex, the outer portion of the adrenal glands located at the top of the kidneys. Physicians often use cortisol tests to diagnose serious adrenal disorders. If a physician determines that a person has abnormal cortisol levels, he will often perform additional testing to confirm a diagnosis.
Function
Cortisol is the primary stress hormone in the body. Cortisol is essential for immune function, inflammatory response, proper glucose metabolism, controlling the release of insulin for blood sugar maintenance and regulation of blood sugar. MayoClinic.com explains that cortisol also controls the body's fight-or-flight response when the body senses danger, shutting down non-essential functions when necessary. When the body continuously activates the body's stress response an overexposure to cortisol may occur. Over time, this can lead to heart disease, sleep problems, depression, obesity, memory loss, skin conditions and digestive problems.
Testing
Testing for cortisol levels most commonly involves a blood sample, though, in some cases, physicians will test cortisol levels in a urine sample. A lab technician will access the blood by inserting a small needle into the vein and capturing the blood in a tube. For a urine sample, physicians will provide the patient with a specimen cup, then transfer the urine into a labeled tube for a lab to process.
Low Levels
When cortisol levels are low, this can indicate hypopituitarism or Addison's disease. Hypopituitarism occurs when the pituitary gland fails to produce normal amounts of some or all of the hormones, according to the National Institutes of Health. Symptoms of hypopituitarism may include abdominal pain, decreased appetite, lack of sex drive, low blood pressure, short stature and weakness.
Addison's disease occurs when the adrenal glands do not produce enough cortisol. Addison's disease most often occurs from damage to the adrenal cortex such as an autoimmune disease, infections, hemorrhage or tumor. Symptoms can include paleness, fatigue, loss of appetite, mouth lesions, nausea, vomiting and diarrhea.
Elevated Levels
An elevated cortisol level may indicate an adrenal or ectopic ACTH-producing tumor. It can also indicate a disease known as Cushing's syndrome. Cushing's syndrome, sometimes known as hypercortisolism, is most commonly caused by oral corticosteroid medication use, according to MayoClinic.com. Symptoms of Cushing's syndrome may include weight gain; fatty tissue deposits in the face and upper back; pink or purple stretch marks around the skin of the thighs, breasts, arms and abdomen; acne; and slow healing.
Considerations
The National Institutes of Health explains that cortisol levels fluctuate throughout the day and repeat on a 24-hour cycle, with the highest levels occurring between 6 to 8 a.m. and lowest levels at around midnight. Physical and emotional stress will affect cortisol levels and can skew results. Birth control pills will cause women to have higher levels of cortisol.
