17-OH progesterone17-hydroxyprogesterone; Progesterone - 17-OH
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.
Normal and abnormal values differ for babies born with low birth weight. In general, normal results are as follows:
- Cord blood - 1,000 - 3,000 ng/dL
- >24 hours - less than 100 ng/dL
- Adults - less than 200 ng/dL
Note: ng/dL = nanograms per deciliter.
Note: Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.
The examples above show the common measurements for results for these tests. Some laboratories use different measurements or may test different specimens.
What Abnormal Results Mean
High levels of 17-OH progesterone may be due to:
In infants with CAH, 17-OHP levels range from 2,000 - 40,000 ng/dL. In adults, a level greater than 200ng/dL may be due to nonclassical adrenal hyperplasia.
Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.
Other risks may include:
- Excessive bleeding
- Fainting or feeling light-headed
- Hematoma (blood accumulating under the skin)
- Infection (a slight risk any time the skin is broken)
Your doctor may suggest an ACTH test if your 17-OH progesterone level is between 200 - 800 ng/dL.
Fritz MA, Speroff L. Normal and abnormal sexual development. In: Speroff L, Fritz MA, eds. Clinical Gynecologic Endocrinology and Infertility. 8th ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 2011:chap 9.
Lambert SM, Vilain EJ, Kolon TF. A practical approach to ambiguous genitalia in the newborn period. Urol Clin North Am. 2010; 37(2):195-205.
Review Date: 5/31/2011
Reviewed By: Linda Vorvick, MD, Medical Director, MEDEX Northwest Division of Physician Assistant Studies, University of Washington School of Medicine; and Susan Storck, MD, FACOG, Chief, Eastside Department of Obstetrics and Gynecology, Group Health Cooperative of Puget Sound, Bellevue, Washington; Clinical Teaching Faculty, Department of Obstetrics and Gynecology, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.