Cortisol Test

A cortisol test measures the level of cortisol in your blood, urine (pee), or saliva (spit). Cortisol is a hormone made by your adrenal glands, two small glands that sit above your kidneys. Hormones are chemical messengers in your bloodstream that control the actions of certain cells or organs.

Cortisol affects almost every organ and tissue in your body. It helps your body: Respond to stress (cortisol is sometimes called the 'stress hormone.'); Reduce inflammation (swelling); Control blood glucose (also called 'blood sugar') and metabolism (how your body uses food for energy); Control your blood pressure; Your pituitary gland, a gland in your brain, makes another hormone, called ACTH (adrenocorticotropic hormone). ACTH tells your adrenal glands how much cortisol to make.

If your cortisol levels are too high or too low, it may mean you have a problem with your adrenal glands or your pituitary gland. High cortisol levels may also be caused by a tumor that makes cortisol, or taking large doses of certain steroid medicines, such as prednisone, for a long time. Low levels may happen if you stop the medicine suddenly.

Without treatment, cortisol levels that are too high or too low can be very serious.

Why this test is done

You may need a cortisol test if you have symptoms of a condition that affects cortisol levels.

• Symptoms of Cushing's syndrome (too much cortisol) may include:
• Weight gain
• Thin arms and legs
• Round face
• Increased fat around the base of your neck or between your shoulder blades
• Easy bruising
• Wide purple streaks on your stomach, breasts, hips, and under your arms
• Muscle weakness
• Common symptoms of Addison disease and adrenal insufficiency (too little cortisol) may include:
• Long-lasting fatigue
• Muscle weakness
• Loss of appetite
• Weight loss
• Abdominal (belly) pain

How to prepare

The preparations for a cortisol test will depend on the type of test you are having. Be sure to follow all the instructions that your provider gives you.

Stress and exercise can raise your cortisol levels, so you may need to rest before your test. For a blood test, you'll need two appointments at different times on the same day. Before a saliva test, you may need to stop using certain medicines.

Let your provider know about all the medicines you use, including skin creams. But don't stop using any medicines without talking with your provider first.

Sample type

Blood Urine Saliva

Other names for this test

urinary cortisol, salivary cortisol, free cortisol, blood cortisol, plasma cortisol, cortisol serum, 24-hour urinary cortisol excretion, 24-hour urinary free cortisol (UFC), late-night salivary cortisol, cortisol competitive protein binding assay, cortisol fluorometric assay