17-Hydroxyprogesterone (17-OHP) Test

Reviewed

Also called: 17-OH progesterone, 17-OHP, 17 alphahydroxyprogesterone, 17 hydroxy progesterone: serum, progesterone: 17-hydroxy

This test measures the amount of 17-hydroxyprogesterone (17-OHP) in your blood. 17-OHP is a substance made by the adrenal glands. The test is used to help diagnose and monitor congenital adrenal hyperplasia (CAH), most commonly due to 21-hydroxylase deficiency. It is part of routine newborn screening for severe CAH and may also be used in children, teens, and adults with symptoms of mild CAH. Results are not diagnostic by themselves and must be interpreted by your clinician along with other tests and your medical history.

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

No special preparation is needed.

Blood draw from a vein (older children and adults) or heel stick (newborns).

There is very little risk from a blood test. You may have slight pain or bruising at the needle site, but most symptoms go away quickly. For newborns, a small bruise may form on the heel but should go away quickly.

Understanding results

Your 17-OHP test result is a number that your clinician will compare to the reference range provided by the laboratory that performed the test. The result alone does not diagnose a condition.

  • Normal 17-OHP level: A normal amount of 17-OHP suggests that you or your child probably do not have congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency. Limitation: A normal result does not rule out all forms of CAH or other conditions. Next step: If symptoms persist, your provider may order other tests to find the cause.
  • High 17-OHP level: Higher than normal levels of 17-OHP suggest that you or your child probably have CAH, most commonly due to 21-hydroxylase deficiency. Limitation: High levels can also occur in other conditions; this result is not diagnostic by itself. Next step: Your provider may order additional tests to learn more about how CAH is affecting you or your child.
  • Decreasing 17-OHP level over time (on treatment): If you are being treated for CAH, decreasing levels of 17-OHP over time indicate that treatment is working. Limitation: This pattern applies only if you are already diagnosed and on treatment. Next step: Your provider will use this information to adjust your treatment plan as needed.
  • 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 results are unclear, your provider may order an ACTH stimulation test, which measures 17-OHP and cortisol levels before and after an ACTH injection.

  • 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

U.S. National Library of Medicine: 17-Hydroxyprogesterone (17-OHP) Test

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