Cortisol Test

Why am I having this test?

Cortisol is a hormone that plays an important role in many bodily functions. It helps regulate blood pressure and blood sugar (glucose) levels, aids digestion, and triggers the "fight or flight" reaction that your body uses to respond to stressful situations.

• Hypopituitarism.
• Acute adrenal crisis.
• A tumor of the adrenal gland.
• Cushing syndrome or disease.
• Addison disease, also called adrenal insufficiency.

What is being tested?

This test measures the amount of cortisol in your body.

What kind of sample is taken?

• The most common way to measure cortisol in the body is to measure it in the blood. Blood samples are usually collected at 8:00 a.m. (when cortisol is highest) or at 4:00 p.m. (when it is lower). In some cases, it may be taken at midnight when cortisol is lowest. A blood sample is usually collected by inserting a needle into a blood vessel.
• Saliva tests are usually done around midnight. This is done by swabbing the inside of your cheeks with a cotton swab.
• Urine samples might include only one sample, or you may be asked to collect all of the urine you produce during a 24-hour period.

How do I collect samples at home?

You may be asked to collect urine at home, possibly over a period of 24 hours. Follow instructions from a health care provider about how to collect the sample.

• Use supplies and instructions that you received from the lab.
• Collect urine only in the germ-free (sterile) container that you received from the lab.
• Do not let any toilet paper or stool (feces) get into the container.
• Refrigerate the sample until you can return it to the lab.
• Return the sample to the lab as instructed.

How do I prepare for this test?

• If you will have a blood test, you may be instructed to:
  • Avoid exercise that takes a lot of effort (vigorous exercise) before the test.
  • Avoid stress before the test.
  • Stop taking certain medicines. These may include:
    • Certain anti-seizure medicines.
    • Androgens.
    • Estrogen.
    • Glucocorticoids (cortisone).
• If you will have a saliva test, follow instructions from your health care provider about when to stop eating, drinking, and using toothpaste before the test.
• If you will have a urine test, no preparation is needed.

Tell a health care provider about:

• Any allergies you have.
• All medicines you are taking, including vitamins, herbs, eye drops, creams, and over-the-counter medicines.
• Any blood disorders you have.
• Any surgeries you have had.
• Any medical conditions you have.
• Whether you are pregnant or may be pregnant.

How are the results reported?

Your test results will be reported as a value that tells you how much cortisol is in your body. Different units may be used for blood, saliva, and urine.

• Blood:
  • Adult: morning blood test (8:00 a.m.): 5–23 mcg/dL.
  • Adult: evening blood test (4:00 p.m.): 3–13 mcg/dL.
  • Child 1–16 years: morning blood test (8:00 a.m.): 3–21 mcg/dL.
  • Child 1–16 years: evening blood test (4:00 p.m.): 3–10 mcg/dL.
  • Newborn: 1–24 mcg/dL.
• Saliva:
  • 7:00 a.m. to 9:00 a.m.: 100–750 ng/dL.
  • 3:00 p.m. to 5:00 p.m.: less than 401 ng/dL.
  • 11:00 p.m. to midnight: less than 100 ng/dL.
• Urine:
  • Adult: less than 100 mcg per 24 hours.
  • Adolescent: 5–55 mcg per 24 hours.
  • Child: 2–27 mcg per 24 hours.

What do the results mean?

Results within the reference ranges are considered normal.

• Cushing syndrome.
• Tumors near the pituitary gland or on an adrenal gland.

• Addison disease.
• Certain medicines, such as chemotherapy and glucocorticoid medicines.
• Hypopituitarism.

If you have an abnormal result, you may need more than one cortisol test because cortisol levels can vary throughout the day and affect your test results.

Talk with your health care provider about what your results mean.

Questions to ask your health care provider

• When will my results be ready?
• How will I get my results?
• What are my treatment options?
• What other tests do I need?
• What are my next steps?

Summary

• A cortisol test may be done to check for problems with the glands associated with cortisol production (pituitary gland and adrenal glands).
• This test may be done using a sample of blood, urine, or saliva.
• A cortisol level that is higher than normal can be seen in Cushing syndrome and in adrenal or pituitary gland tumors.
• A cortisol level that is lower than normal can be seen in Addison disease, with use of certain medicines, and in hypopituitarism.