To screen for, detect, and monitor treatment for congenital adrenal hyperplasia (CAH); sometimes to help rule out other conditions with similar symptoms
17-Hydroxyprogesterone
As part of a routine newborn screen when an infant's sex is not obvious (ambiguous genitalia); when a female has increased growth of facial and body hair (hirsutism) or other symptoms that could be related to elevated male sex hormones; when a male child has premature sexual development; periodically to monitor CAH treatment
A blood sample drawn from a vein in your arm or blood from a heelstick for an infant
None, but an early morning collection may be requested; it may also be requested that the blood sample be collected at a specific time during a woman's menstrual cycle. The test should not be ordered if the patient is taking steroids.
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How is it used?
The 17-hydroxyprogesterone (17-OHP) test is used to screen for congenital adrenal hyperplasia (CAH) and may be used along with other tests to help diagnose and monitor CAH.
Screening
- The 17-OHP test is routinely ordered as part of newborn screening in the United States to detect CAH due to 21-hydroxylase deficiency.
- The 17-OHP test may be used to screen for CAH in older children or adults before symptoms appear or to confirm a CAH diagnosis in people with symptoms.
Diagnosis
- Measurement of 17-OHP in the blood may be used to aid in the diagnosis of CAH in older children and adults who may have a milder, "late-onset" form.
Monitoring
- If someone is diagnosed with 21-hydroxylase deficiency, a 17-OHP test along with plasma renin activity, androstenedione and testosterone tests may be used periodically to monitor the effectiveness of treatment.
Ruling out CAH
- A 17-OHP test may also sometimes be used, along with other hormone tests, to help rule out CAH in women who have symptoms such as excess facial and body hair and irregular periods. This includes women with suspected polycystic ovarian syndrome (PCOS) and infertility, and rarely those with suspected adrenal or ovarian cancers.
17-OHP testing, especially the newborn screening test, may produce false-positive results. If the level is elevated but not so high that it is diagnostic of CAH, other tests may be performed, such as:
- Plasma renin activity
- Androstenedione
- Testosterone
Other tests
- An ACTH stimulation test may be also be ordered as a follow-up test. In CAH, ACTH stimulation will markedly increase 17-OHP levels.
- Genetic testing may be performed to detect CYP21A2 gene mutations that can cause the condition.
- A karyotype test may be ordered as a follow-up test to detect chromosome disorders and to help determine a baby's sex.
- Electrolytes may be ordered to measure the person's sodium and potassium levels.
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When is it ordered?
The 17-OHP test is ordered routinely as part of a newborn screen and may be repeated if the screening test is elevated in order to confirm the initial results.
A 17-OHP test may be ordered when an infant or young child has signs and symptoms of adrenal insufficiency or of CAH. Some signs and symptoms may include:
- Listlessness, lack of energy (lethargy)
- Not eating well
- Skin color that looks more tanned than would be otherwise expected
- Dehydration
- Low blood pressure
- Sex organs that are not clearly male or female (ambiguous genitalia)
- Development of male secondary sex characteristics (virilization)
- Acne
This test may sometimes be ordered in older children or in adults when the milder form of CAH (late-onset) is suspected. The 17-OHP test may also be conducted when a girl or woman is experiencing symptoms that may be due to CAH or may be due to another condition, such as PCOS. Symptoms may include:
- Excess facial and body hair (hirsutism)
- Lack of or irregular menstrual periods (menses)
- Development of male secondary sex characteristics
- Infertility
Testing may be performed on boys or men when they experience:
- Early (precocious) puberty
- Infertility
When a person has been diagnosed with 21-hydroxylase deficiency, then a 17-OHP test may be ordered periodically to monitor the effectiveness of treatment.
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What does the test result mean?
If a newborn or infant has significantly elevated concentrations of 17-OHP, then it is likely that he or she has CAH. If a person has moderately increased levels, then that person may have a less severe case of CAH or may have an 11-beta-hydroxylase deficiency (another enzyme defect that is associated with CAH).
Normal 17-OHP results mean that it is likely that the person tested does not have CAH due to a 21-hydroxylase deficiency.
Low or decreasing concentrations in a person with CAH indicate a response to treatment. High or increasing levels may indicate that changes in treatment are required.
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Is there anything else I should know?
Sometimes an ACTH stimulation is required to increase the diagnostic accuracy of the 17-OHP test. This test involves measuring the level of cortisol in a person's blood before and after an injection of synthetic ACTH. In CAH, ACTH stimulation will markedly increase 17-OHP levels.
Premature infants often have elevated levels of 17-OHP. The newborn screen may need to be repeated at a later time.
Rarely, prenatal 17-OHP testing may be performed on amniotic fluid to detect and treat CAH in the fetus during pregnancy. Treatment of the fetus before birth is controversial.
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Can I have CAH if no CYP21A2 gene mutations were detected during genetic testing?
Yes. Testing detects the most common mutations but will not detect those that are rare. If a specific mutation has been identified in your family members, then you should be tested for that mutation. Also, this test only detects CAH due to 21-hydroxylase deficiency. Other, less common types of CAH will not have mutations in the CYP21A2 gene.
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Should I tell all of my healthcare practitioners if I have CAH?
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If I have CAH, or my child does, should my family members be tested?
You should talk to your healthcare practitioner or a genetic counselor about this. Since CAH is caused by an autosomal recessive genetic mutation, both parents must have an altered gene in order for a child to have the condition. If both parents are carriers then each child has a 25% chance of having the condition.
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How long will it take for 17-hydroxyprogesterone results?
This depends on the laboratory performing the test. 17-OHP testing requires specialized equipment and is not offered by every laboratory. It may be necessary to send your blood sample to a reference laboratory and it may be several days to weeks for results to be available.
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How can the healthcare practitioner determine the sex of a baby with sex organs that are not clearly male or female?
Chromosome analysis (karyotyping) can be performed to identify whether the baby has XX (female) or XY (male) sex chromosomes.

