What is a 17-OH Progesterone test?
The 17-OH Progesterone (17-Hydroxyprogesterone) test measures the amount of 17-hydroxyprogesterone in your blood.
17-OH progesterone is a hormone produced mainly by the adrenal glands and, to a lesser extent, by the ovaries or testes. It is an intermediate substance used by the body to produce other steroid hormones, including cortisol.
The test is particularly useful for evaluating certain disorders of adrenal hormone production, especially congenital adrenal hyperplasia (CAH) caused by 21-hydroxylase deficiency.
What is the 17-OH Progesterone test used for?
The test may be used to:
Screen newborns for congenital adrenal hyperplasia (CAH).
Help diagnose CAH in children, adolescents, or adults.
Investigate excessive production of androgens (male-type hormones).
Evaluate symptoms such as early puberty, excessive facial or body hair, acne, or irregular menstrual periods in females.
Investigate unexplained adrenal hormone abnormalities.
Help monitor some patients with known congenital adrenal hyperplasia.
Why do I need a 17-OH Progesterone test?
Your doctor may request this test if you have signs or laboratory findings suggesting abnormal adrenal hormone production.
In females, testing may be considered when there is:
Irregular or absent menstrual periods
Excessive facial or body hair (hirsutism)
Severe or persistent acne
Signs of increased androgen production
Difficulty becoming pregnant
In children, the test may be requested because of early puberty, atypical genital development, or abnormal newborn screening results.
In males or females, it may also be ordered when there is unexplained adrenal dysfunction or suspected congenital adrenal hyperplasia.
What happens during the test?
A healthcare professional will collect a blood sample from a vein in your arm using a small needle.
The sample is sent to the laboratory for measurement of 17-OH progesterone, usually using an immunoassay or other validated laboratory method.
Will I need to do anything to prepare?
Usually, no special preparation or fasting is required.
However, the timing of the sample can be important because 17-OH progesterone levels can vary according to:
Time of day
Age
Sex
Menstrual cycle phase
Pregnancy
Medications
Hormonal conditions
For females who are menstruating, your doctor or laboratory may recommend collecting the sample during a particular phase of the menstrual cycle, often in the early follicular phase, depending on the reason for testing.
Follow your healthcare provider's instructions regarding the appropriate timing of the test.
Are there any risks?
The test involves a routine blood sample. You may experience mild discomfort, bruising, or slight bleeding at the needle site.
Serious complications are uncommon.
What do the results mean?
17-OH progesterone results must be interpreted according to the person's age, sex, clinical condition, menstrual cycle phase, pregnancy status, and the laboratory's reference range.
High 17-OH Progesterone
An elevated level may occur with:
Congenital adrenal hyperplasia (CAH), particularly 21-hydroxylase deficiency
Increased adrenal androgen production
Certain adrenal disorders
Some ovarian conditions
Pregnancy or other physiological conditions
A mildly elevated result does not necessarily mean that a person has CAH. Further testing may be required, especially when the result is borderline.
Depending on the clinical situation, your doctor may request an ACTH stimulation test or additional adrenal and androgen hormone tests.
Normal 17-OH Progesterone
A normal result generally indicates that there is no significant elevation of 17-OH progesterone at the time of testing.
However, a normal result does not completely exclude every form of congenital adrenal hyperplasia or other adrenal disorders, particularly if the test was performed at an inappropriate time or under conditions that affect hormone levels.
Low 17-OH Progesterone
A low level is generally less clinically significant than an elevated level and should be interpreted together with other adrenal hormones and the patient's clinical findings.
Important note about the results
17-OH progesterone is not the same hormone as progesterone. They are different steroid hormones and are used for different clinical purposes.
The interpretation of 17-OH progesterone is particularly dependent on age, sex, menstrual cycle phase, time of collection, pregnancy status, and the laboratory method used.
If the result is elevated, additional tests such as cortisol, ACTH, androstenedione, testosterone, DHEA-S, or an ACTH stimulation test may be recommended to determine the cause.
Your healthcare provider should interpret the result together with your symptoms and other laboratory findings.
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