17-Hydroxyprogesterone (17-OHP) Test
Reviewed
Also called: 17-OH progesterone, 17-OHP, 17 alphahydroxyprogesterone, 17 hydroxy progesterone: serum, progesterone: 17-hydroxy
A 17-hydroxyprogesterone test measures the amount of 17-hydroxyprogesterone (17-OHP) in a sample of your blood. 17-OHP is a substance that your adrenal glands make.
Specimen: Blood
Why this test may be ordered
- To check all newborns for severe (classic) CAH as part of routine newborn screening.
- To help diagnose mild (nonclassic) CAH in children, teens, and adults with symptoms.
- To find out if treatment for CAH is working.
- To help rule out CAH in women with symptoms such as excess facial hair and irregular periods.
Preparation and collection
There are no special preparations needed for a 17-OHP test.
For a newborn screening, a health care professional will clean your baby's heel with alcohol. For older children and adults, a health care professional will take a blood sample from a vein in your arm, using a small needle. This usually takes less than five minutes.
There is very little risk from a blood test. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly. Your baby may feel a little pinch when the heel is poked.
Understanding results
The results of a 17-OHP test help show whether you or your child have the most common type of CAH (21-hydroxylase deficiency).
- Normal 17-OHP level: If test results show a normal amount of 17-OHP, it means that you or your child probably do not have CAH with 21-hydroxylase deficiency. Limitation: If the results of your 17-OHP test aren't clear, your provider may order another test to measure your 17-OHP. Next step: If you or your child has symptoms, your provider may order other tests to figure out the cause.
- High 17-OHP level: If test results show higher than normal levels of 17-OHP, you or your child probably has CAH. Limitation: If your newborn's 17-OHP levels are only slightly elevated, it may not necessarily mean your baby has CAH. Next step: Your provider may order other tests to learn more about how CAH is affecting you or your child.
- Decreasing 17-OHP level over time (on treatment): If you or your child is being treated for CAH, decreasing levels of 17-OHP over time means that the treatment is working. Limitation: Treatment for CAH is usually only recommended if you or your child has symptoms. Next step: If you, your child, or another family member has been diagnosed with CAH, you may want to talk with a genetic counselor.
- This test is not diagnostic by itself; results must be interpreted by a clinician along with other tests and clinical findings.
- Newborn screening is most accurate when done more than 24 hours after birth; if tested sooner, a repeat test may be needed.
- Newborn screening cannot detect mild (nonclassic) CAH.
What to do next
If you have questions about the results of a 17-OHP test, talk with your provider.
- What do my 17-OHP levels mean in my specific situation?
- Do I need any follow-up tests?
- Should I see a genetic counselor?
Evidence source
Source: U.S. National Library of Medicine (MedlinePlus). Practices and reference ranges may differ in your country.
U.S. National Library of Medicine: 17-Hydroxyprogesterone (17-OHP) Test