What Is the 17-OH Progesterone Test?
The hormone 17-hydroxyprogesterone (17-OH progesterone) is produced by the adrenal glands. These are two small glands. One is located on top of each kidney. Along with special enzymes, or proteins, 17-OH progesterone is converted to a hormone called cortisol. Cortisol is constantly released in varying amounts, but high levels are released during times of physical or emotional stress. Cortisol is also important in regulating metabolism and the immune system.
A cortisol deficiency can occur in people who lack the appropriate enzymes, which can lead to a buildup of 17-OH progesterone in the blood. High levels of 17-OH progesterone can indicate a condition called congenital adrenal hyperplasia (CAH). CAH is a glandular disorder that results in the adrenal glands being unable to create sufficient cortisol, and it may increase the production of male sex hormones called androgens.
CAH can occur in both boys and girls. Young children with CAH may have ambiguous genitalia, pubic hair, or acne. The condition can also develop later in life in less obvious ways. Some common symptoms include clearly defined muscle tone, increased body hair, and a deeper voice.
In infants, CAH can sometimes cause dehydration or shock, both of which are very serious conditions. As a result, the 17-OH progesterone test should be part of every newborn’s initial medical examination. The test is routinely given to newborns in the United States to screen for CAH.
A doctor will usually order a 17-OH progesterone test for a young child, teenager, or adult who displays some of the classic symptoms of CAH. The sooner a person with CAH is diagnosed and treated, the less likely they are to experience complications.
Why a 17-OH Progesterone Test Is Performed
The 17-OH progesterone test is important for all newborn babies. However, the test should also be considered for anyone who develops symptoms of CAH later in life.
The signs and symptoms of CAH in infants include:
- genitals that are ambiguous, which means not clearly male or female
- pubic hair
- a lack of energy
- disinterest in eating
- low blood pressure
Signs and symptoms in young girls and adult women include:
- irregular periods
- a deep voice
- genitalia that has both male and female characteristics, but appear more male
- excessive hair growth
- early hair growth in the pubic and armpit area
Signs and symptoms in young boys and adult men include:
- early onset of puberty, beginning as early as age 2 or 3
- a deep voice
- well-defined muscles
- a large penis and small testes
Keep in mind that anyone who has been diagnosed with CAH should be tested periodically so the condition can be monitored. Changes in 17-OH progesterone levels may indicate a need for an adjustment in treatment.
How to Prepare for a 17-OH Progesterone Test
Your doctor may instruct you to stop eating and drinking for at least eight hours before the test to ensure accurate results. Fasting usually isn’t necessary for infants. Your doctor may also ask you to temporarily stop taking any medications that could affect the results. Certain medications, including birth control pills and corticosteroids, can interfere with the accuracy of the test. However, you shouldn’t stop taking any medications unless your doctor tells you to do so.
If your child is getting tested, make sure they wear loose, comfortable clothing. This can make it easier for the technician to perform the blood test.
Ask your doctor or your child’s doctor for more specific directions.
How a 17-OH Progesterone Test Is Performed
A 17-OH progesterone test involves taking a small sample of blood. Blood is usually drawn from a vein or artery in the hand or in the bend of the elbow. The following will occur:
- A healthcare provider will first clean the area with an antiseptic and then tie an elastic band around your arm. This will make your veins swell with blood.
- Once they find a vein, they’ll insert the needle. You can expect to feel a slight prick or stinging sensation when the needle goes in. However, the test itself isn’t painful. They'll only collect enough blood as needed to perform the test and any other blood tests your doctor may have ordered.
- After enough blood has been drawn, they’ll remove the needle and place a bandage over the puncture site.
- They’ll then tell you to apply pressure to the area with your hand for a few minutes.
- The blood sample will then be sent to a laboratory for analysis.
- Your doctor will follow up with you to discuss the results.
A simple heel prick is enough to provide an adequate blood sample for infants. A healthcare provider will use a sharp tool called a lancet to prick the skin. They’ll then collect the sample of blood and cover the puncture site with a bandage.
Risks of a 17-OH Progesterone Test
Blood tests carry few risks. Some people have a slight bruise or experience soreness around the area where the needle was inserted. However, this usually goes away within a few days.
The risks from blood tests are rare, but they can occur. Such risks include:
- excessive bleeding
- blood accumulating under the skin, or a hematoma
- infection at the puncture site
17-OH Progesterone Test Results
The results of a 17-OH progesterone test depend on many variables, including age, sex, and testing methods. This can make it difficult to identify normal and abnormal test results. Make sure to meet with the doctor to discuss what the 17-OH progesterone test results mean for you or your child.
In general, normal results for various age groups include:
- newborns: 1,000-3,000 nanograms/deciliter (ng/dL)
- babies older than 24 hours: less than 100 ng/dL
- adults: less than 200 ng/dL
High levels of 17-OH progesterone in the blood may indicate CAH. Infants with CAH tend to have 17-OH progesterone levels ranging from 2,000 to 4,000 ng/dL, while adults with CAH usually have 17-OH progesterone levels above 200 ng/dL.
High 17-OH progesterone levels could also indicate the presence of an adrenal tumor, which can also affect hormone levels. Further testing may be required to determine the specific cause of increased CAH levels.