Cortisol Test
Reviewed
Also called: Cortisol Test, Urinary cortisol, Salivary cortisol, Free cortisol, Blood cortisol, Plasma cortisol
A cortisol test measures the level of cortisol in your blood, urine (pee), or saliva (spit).
Specimen: Blood, urine (24-hour collection or single morning sample), or saliva
Why this test may be ordered
- Symptoms of Cushing's syndrome (too much cortisol): weight gain, thin arms and legs, round face, increased fat around the base of the neck or between the shoulders, easy bruising, wide purple streaks on the stomach, breasts, hips, and under the arms, muscle weakness.
- Symptoms of Addison disease and adrenal insufficiency (too little cortisol): long-lasting fatigue, muscle weakness, loss of appetite, weight loss, abdominal pain.
- To monitor treatment for conditions affecting cortisol levels.
Preparation and collection
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.
Most of your cortisol is in your blood, so cortisol tests often use a sample of blood drawn at a lab. But some cortisol passes into your urine and saliva. Blood samples are usually taken twice during the day--once in the morning when cortisol levels are normally at their highest, and again around 4 p.m., when levels are normally much lower.
There is very little risk to having a blood test. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly. There are no known risks to a urine or saliva test.
Understanding results
A cortisol test alone can't diagnose the cause of abnormal cortisol levels. If your cortisol level isn't normal, you will usually have more tests to find out what is causing the problem.
- High cortisol level: High levels of cortisol may be a sign that you have Cushing's syndrome. Limitation: If your cortisol results aren't normal, it doesn't always mean you have a medical condition that needs treatment. Cortisol levels can also be affected by: Stress, Pregnancy, Exercise, Hot and cold temperatures, Certain medicines, such as birth control pills. Next step: If your cortisol level isn't normal, you will usually have more tests to find out what is causing the problem.
- Low cortisol level: Low levels of cortisol may mean you have Addison disease or secondary adrenal insufficiency. Limitation: The most common cause of abnormal cortisol levels is taking steroid medicines for a long time or suddenly stopping them. Next step: To learn what your test results mean, talk with your provider.
- A cortisol test alone cannot diagnose the cause of abnormal cortisol levels; additional testing is needed.
- Cortisol levels can be affected by stress, pregnancy, exercise, hot and cold temperatures, certain medicines (e.g., birth control pills), and steroid medicine use or sudden discontinuation.
- High cortisol levels may come and go in some people (pseudo-Cushing's syndrome), which may be caused by depression, anxiety, alcohol use disorder, poorly controlled diabetes, obesity, and other health problems.
What to do next
To learn what your test results mean, talk with your provider.
- What do my cortisol test results mean?
- Do I need additional tests to confirm a diagnosis?
- Could my medicines or other factors affect my cortisol levels?
Evidence source
Source: U.S. National Library of Medicine (MedlinePlus). Practices and reference ranges may differ in your country.