17-OHP test: what 17-hydroxyprogesterone shows and who needs it

A 17-OHP test measures 17-hydroxyprogesterone, a substance your adrenal glands make on the way to making cortisol. It is not a stress test or a general hormone check. It is a specific test that helps find congenital adrenal hyperplasia (CAH), a group of inherited adrenal disorders, and it is part of routine newborn screening in the United States.

If you came here with a result or a request from a clinician, this page explains what the test is for. If you came here because you are tired or stressed, it probably isn’t the test you need.

What 17-OHP is and why it matters

Your adrenal glands turn 17-OHP into cortisol, using an enzyme called 21-hydroxylase. MedlinePlus explains that in the most common type of CAH a gene change means the body can’t make enough of that enzyme. 17-OHP builds up, and the adrenal glands use the extra to make more male sex hormones (androgens) than usual. That happens in people of both sexes, which is why testosterone tests are often ordered alongside 17-OHP.

NICHD says CAH can also mean too little cortisol and, in about three-quarters of cases, too little aldosterone, the hormone that helps balance sodium, water and blood pressure.

MedlinePlus Genetics says the classic forms of 21-hydroxylase deficiency occur in about 1 in 15,000 newborns, and the nonclassic form is estimated at about 1 in 1,000 people. It adds that this enzyme problem accounts for about 95 percent of CAH.

Who gets a 17-OHP test

MedlinePlus lists these uses:

• Newborn screening. All newborns are checked for severe (classic) CAH. In a hospital birth, the test is done with a few drops of blood from the heel before going home. The test is most accurate when done more than 24 hours after birth, and some states require two tests. Newborn screening can’t find the milder form.
• Children, teens and adults with symptoms of nonclassic CAH. In children these include fast growth that stops early, early puberty and severe acne. In girls and women: more facial and body hair than usual, irregular or absent periods, thinning hair on the head and trouble getting pregnant. In boys and men: enlarged penis with small testicles and a low sperm count.
• Women with extra facial hair and irregular periods, to help rule CAH out. MedlinePlus says polycystic ovary syndrome (PCOS) can cause the same symptoms.
• People already treated for CAH, to see whether treatment is working. Falling 17-OHP levels over time mean it is.

A 2022 review of how PCOS is told apart from adrenal disorders says nonclassic CAH and PCOS share many features and are hard to separate by examination and ultrasound alone. It calls the basal and ACTH-stimulated 17-OHP level the most important measurement, taken early in the menstrual cycle when a woman has periods. See cortisol and PCOS for the wider picture.

For parents: signs in a baby

MedlinePlus says classic CAH can be life-threatening without diagnosis and treatment, and that symptoms may start within days or weeks of birth. They include lack of energy, vomiting and feeding problems, diarrhea, dehydration, low blood pressure, an irregular heartbeat, shock and poor weight gain. If a baby has these signs, get urgent medical care. Call 911 or go to the nearest emergency room. Don’t wait for a test or an appointment.

How the test is done

• Newborns: a heel prick to collect a few drops of blood.
• Older children and adults: a blood draw from the arm, taking under five minutes.
• Preparation: MedlinePlus says no special preparation is needed.

What the results mean

MedlinePlus says the following about results:

• A normal level means you or your child probably doesn’t have CAH from 21-hydroxylase deficiency. If symptoms continue, a provider may order other tests to find the cause.
• A higher than normal level means CAH is probable, and more tests will show how it is affecting you or your child.
• A slightly high newborn level doesn’t necessarily mean CAH. Providers do other tests to confirm or rule it out.
• An unclear result may lead to an ACTH stimulation test, where cortisol and 17-OHP are measured before and after an ACTH injection. In CAH, 17-OHP rises a lot and cortisol doesn’t.

This page gives no cut-off numbers. Labs print their own ranges, and the right comparison depends on age, sex and, for women with periods, the point in the cycle. Go over the number on your report with the clinician who ordered it.

How it relates to other adrenal tests

If the question is about	A test that fits
Whether you make too little cortisol	Cortisol, ACTH and sometimes a stimulation test. See low cortisol
Other adrenal androgens	DHEA sulfate. MedlinePlus says DHEA-S can be high in CAH. See DHEA-S
The pituitary signal to the adrenal glands	ACTH. See ACTH blood test

A cortisol test alone can’t diagnose the cause of an abnormal cortisol level, and it can’t diagnose CAH. If CAH runs in your family, MedlinePlus suggests a genetic counselor can help you understand how likely it is to pass to future children.

Questions people ask

What is a 17-hydroxyprogesterone test used for?

To help diagnose and monitor CAH, mainly 21-hydroxylase deficiency, and to help rule it out in women with symptoms that PCOS could also cause.

Is the 17-OHP test part of a normal hormone panel?

It is part of routine newborn screening. Beyond that, MedlinePlus describes it as a test used when CAH is suspected or being monitored, not as a general check.

Can I have CAH and not know?

Yes. NICHD says some people have the nonclassic form and never know it, and MedlinePlus Genetics says some people with the nonclassic type have no symptoms at all.

Does a normal 17-OHP rule out an adrenal problem?

No. MedlinePlus says a normal level means you probably don’t have CAH from 21-hydroxylase deficiency. If you still have symptoms, a provider may order other tests to find the cause.

Keep reading

• All adrenal and related tests

  ACTH, DHEA-S, aldosterone and more.

• DHEA-S blood test

  Another adrenal hormone, and what it can show.

• Cortisol and PCOS

  Where cortisol fits and doesn't fit.

• Low cortisol

  Causes, emergency signs and testing.