Definition of 17-OH progesterone:

17-OH progesterone is a blood test that measures the amount of 17-OH progesterone, a hormone produced by the adrenal glands and gonads.

How the test is performed:

A blood sample is needed. For information on how this is done, see: Venipuncture.

The blood sample is sent to a laboratory for examination.

How to prepare for the test:

Your doctor may tell you to stop taking any drugs that may cause false test results. Such drugs include corticosteroids and birth control pills.

Your doctor may also recommend that the test be done at a specific time of day, since it is sensitive to circadian rhythms, the natural highs and lows that the body experiences during a 24-hour period.

How the test will feel:

When the needle is inserted to draw blood, you may feel moderate pain, or only a prick or stinging sensation. Afterward, there may some throbbing.

Why the test is performed:

This test is mainly used to check infants for an inherited disorder that affects the adrenal gland, called congenital adrenal hyperplasia (CAH). It is often performed on infants who are born with outer genitals that do not clearly look like those of a boy or a girl.

This test is also used to identify people who have nonclassical adrenal hyperplasia. This condition occurs when the body does not make enough of a substance that helps the adrenal gland make cortisol.

Your doctor may recommend this test if you are a woman who has excess hair growth in places where adult men grow hair, or if you have male characteristics, such as a deep voice or an increase in muscle mass.