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
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
- 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.
A cortisol test is done to measure the
level of the
hormone cortisol in the blood.
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.
- A high level of cortisol in the blood can
Cushing's syndrome, a disorder that can be caused by
overactive adrenal glands, an adrenal gland tumor, some types of
cancer, or long-term use of
- A high blood cortisol level can be caused by severe liver or
- Pregnancy or birth control pills
can also cause a high blood cortisol level.
- Conditions such as recent surgery, illness, injury, or
whole-body infection (sepsis) can
cause high cortisol levels.
- 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
- Having low blood sugar (hypoglycemia).
- Eating, drinking, or
exercising before the test.
- Taking medicines, such as birth control
amphetamines, or corticosteroids.
- Having a
radioactive scan within 1 week of a cortisol test.