Understanding Your Laboratory Test: What It Is, How It Is Done, and Why It Matters
A blood test measuring 17-hydroxyprogesterone levels after adrenal stimulation to diagnose adrenal gland disorders.
{"Measures hormone levels 1 hour after ACTH stimulation injection","Primarily used to diagnose congenital adrenal hyperplasia (CAH)","Helps evaluate adrenal gland function","Involves blood draw before and after hormone stimulation","Results help doctors distinguish between different adrenal conditions"}
Key facts at a glance
- LOINC
- 48341-2
- Short code
- 17-OHP STIM, 17-Hydroxyprogesterone Challenge, ACTH Stimulation Test
- Synonyms
- 17OHP 1h p chal SerPl-mCnc
- Category
- chemistry
- Sample
- serum
- Container
- Serum Separator Tube (SST/Gel) or Plain Red Top Tube
- Units
- N/A
- Ref low
- 10
- Ref high
- 15
- Critical range
- — – 1000 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- ≥ 0 years
- Method
- Immunoassay (Chemiluminescence or ELISA)
- CPT
- 83498
- SNOMED
- 31315005
- Specimen volume
- 1.0-2.0 mL serum minimum
- Stability
- Room temperature: 24 hours; Refrigerated (2-8°C): 7 days; Frozen (-20°C or below): 30 days. Avoid repeated freeze-thaw cycles.
- Hemolysis max
- 50
- Lipemia max
- 300
- Icterus max
- 20
- TAT
- 24–72 hours
- Order
- routine
This test is a laboratory procedure that measures specific substances in your body to help your healthcare provider assess your overall health, screen for certain conditions, and monitor how well an existing treatment plan is working for you.
The 17-Hydroxyprogesterone (17-OHP) test measures the amount of 17-hydroxyprogesterone in your blood. This is a hormone produced by the adrenal glands, located on top of your kidneys. The test is performed after a stimulation test where you receive an injection of ACTH (adrenocorticotropic hormone), and blood is drawn 1 hour later to see how your adrenal glands respond.
The test is usually performed by collecting a small sample of blood from a vein in your arm, although some tests may use urine, a swab, or another specimen. A trained technician cleans the site, collects the sample, and sends it to a laboratory, and the procedure typically takes only a few minutes.
First, a blood sample is taken from a vein in your arm. Then, you will receive an injection of synthetic ACTH (cosyntropin). After exactly 1 hour, another blood sample is collected. Both samples are sent to a laboratory to measure 17-OHP levels and compare how much your body produces in response to stimulation.
This test is important because it gives your healthcare provider objective information about how your body is functioning. The results can reveal potential health problems before symptoms develop, support an accurate diagnosis, and help track the effectiveness of your treatment over time.
The 17-OHP test helps doctors evaluate how well your adrenal glands are working. It is particularly important for detecting congenital adrenal hyperplasia (CAH), a genetic condition where the adrenal glands produce abnormal amounts of hormones. This test can also help distinguish between different types of adrenal disorders.
Reference range
Post-ACTH stimulation: >10-15 ng/dL (some labs >10 ng/dL) is considered normal response to rule out classic congenital adrenal hyperplasia (CAH). Basal levels: <200 ng/dL (adults), <400 ng/dL (newborns) may warrant stimulation testing.N/A
No fasting required. Patient should inform provider of current medications including corticosteroids, estrogens, androgens, and anticonvulsants as these may affect results. Report any recent illness or stress as this may influence adrenal function. Morning collection preferred (8 AM) for baseline sample.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Elevated 17-OHP levels after ACTH stimulation typically indicate congenital adrenal hyperplasia (CAH), a group of genetic disorders affecting adrenal hormone production. CAH can cause hormonal imbalances leading to early puberty, irregular periods, excessive hair growth, and in severe cases, salt-wasting crises in newborns. The test helps differentiate between classic and non-classic forms of CAH, guiding appropriate treatment and management.
Normal 17-OHP response to ACTH stimulation suggests proper adrenal function. Abnormally low responses may indicate adrenal insufficiency or other adrenal disorders. This test is valuable for evaluating adrenal hormone deficiencies and guiding hormone replacement therapy decisions.
Frequently asked questions
Do I need to fast before this test?
Are there any risks or side effects?
How long does the test take?
When will I get my results?
What happens if my results are abnormal?
Sources
- 1
- 2
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 10, 2026. · Read our editorial policy