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Cortisol in Blood

How It Feels

The blood sample is taken from a vein in your arm. An elastic band is wrapped around your upper arm. It may feel tight. You may feel nothing at all from the needle, or you may feel a quick sting or pinch.

Risks

There is very little chance of a problem from having a blood sample taken from a vein.

  • You may get a small bruise at the site. You can lower the chance of bruising by keeping pressure on the site for several minutes.
  • In rare cases, the vein may become swollen after the blood sample is taken. This problem is called phlebitis. A warm compress can be used several times a day to treat this.
  • Ongoing bleeding can be a problem for people with bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medicines can make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medicine, tell your doctor before your blood sample is taken.

Results

A cortisol test is done to measure the level of the hormone cortisol in the blood.

Normal

The normal values listed here—called a reference range—are just a guide. These ranges vary from lab to lab, and your lab may have a different range for what's normal. Your lab report should contain the range your lab uses. Also, your doctor will evaluate your results based on your health and other factors. This means that a value that falls outside the normal values listed here may still be normal for you or your lab.

Cortisol1
Adult/Child Morning

5–23 micrograms per deciliter (mcg/dL) or 138–635 nanomoles per liter (nmol/L)

Afternoon

3–16 mcg/dL or 83–441 nmol/L

Newborn 

2–11 mcg/dL or 55–304 nmol/L

High values

Low values

  • A low level of cortisol in the blood can be caused by:
    • Problems that affect the adrenal glands directly, such as Addison's disease or a tuberculosis infection of the adrenal glands.
    • Problems with the pituitary gland that affect the adrenal glands, such as cancer or a head injury.

What Affects the Test

Reasons you may not be able to have the test or why the results may not be helpful include:

  • Having physical or emotional stress.
  • Being pregnant. This can cause urine cortisol levels to be high.
  • Having low blood sugar (hypoglycemia).
  • Eating, drinking, or exercising before the test.
  • Taking medicines, such as birth control pills, estrogen, amphetamines, or corticosteroids.
  • Having a radioactive scan within 1 week of a cortisol test.

WebMD Medical Reference from Healthwise

Last Updated: June 20, 2012
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

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