Your Medical Test: What It Is, Why You May Need It, and What to Expect
A blood test measuring 17-hydroxyprogesterone levels after adrenal gland stimulation to evaluate hormone production function.
{"This test measures how well your adrenal glands produce certain hormones","A hormone injection is given to stimulate your adrenal glands before blood samples are taken","It helps diagnose conditions like congenital adrenal hyperplasia (CAH) and adrenal insufficiency","Multiple blood samples are collected over time after the stimulation","Results help your doctor determine if your adrenal glands are functioning properly"}
Key facts at a glance
- LOINC
- 51679-9
- Short code
- 17-OHP
- Synonyms
- 17OHP sp6 p chal SerPl-mCnc
- Category
- chemistry
- Sample
- serum
- Container
- Serum separator tube (SST) or plain red top tube
- Units
- N/A
- Ref low
- 10
- Ref high
- 50
- Critical range
- — – 200 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 0–120 years
- Method
- Immunoassay (Chemiluminescence or ELISA)
- CPT
- 83498
- SNOMED
- 309154007
- Specimen volume
- 1-2 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
- 100
- Icterus max
- 20
- TAT
- 24–72 hours
- Order
- routine
What is this test? This test is a laboratory procedure that measures specific substances or markers in your body. It helps your healthcare provider screen for certain conditions, confirm or rule out a diagnosis, and monitor your overall health over time.
The 17-Hydroxyprogesterone (17-OHP) test measures the level of 17-hydroxyprogesterone in your blood. This is a hormone produced by your adrenal glands, which are small glands located on top of your kidneys. The '6th specimen post ACTH challenge' means this is a blood sample taken after you receive an injection of ACTH (adrenocorticotropic hormone) to stimulate your adrenal glands. This is called an ACTH stimulation test or cosyntropin stimulation test.
How is the test performed? The test is usually performed by a trained healthcare professional in a clinic, hospital, or laboratory. A small sample, such as blood, urine, or tissue, is collected and then analyzed using standard laboratory methods. The collection itself typically takes only a few minutes.
During this test, a healthcare professional will first draw a baseline blood sample. Then, you will receive an injection of synthetic ACTH (cosyntropin) into your muscle or vein. After the injection, additional blood samples will be taken at specific time intervals (typically 30, 60, and 90 minutes later). The '6th specimen' refers to one of these follow-up samples. The entire test usually takes about 1-2 hours to complete.
Why do I need this test? Your doctor may order this test to look for signs of illness, confirm a suspected diagnosis, monitor a chronic condition, or check how well your current treatment is working. The results provide important information that helps guide decisions about your care.
Your doctor may order this test if they suspect you have a disorder affecting your adrenal gland function. The ACTH stimulation test helps evaluate how your adrenal glands respond to stress. It is commonly used to diagnose conditions such as congenital adrenal hyperplasia (CAH), adrenal insufficiency, and certain adrenal tumors. The test can also help distinguish between different types of adrenal disorders.
How should I prepare? Preparation depends on the type of test being done. You may be asked to fast for a certain number of hours, avoid certain foods, drinks, or medications, or drink extra water beforehand. Always follow the specific instructions from your healthcare provider, and tell them about any medications or supplements you take.
Follow your doctor's instructions regarding preparation. You may need to fast (not eat or drink anything except water) for a certain period before the test. Inform your doctor about all medications you are taking, as some medications can affect test results. Birth control pills, corticosteroids, and certain hormones may interfere with the test. Wear a short-sleeved shirt so the healthcare provider can easily access your arm for blood draws.
What happens after the test? After the sample is collected, you can usually return to your normal activities right away. Your sample is sent to a laboratory for analysis, and results are typically available within a few days. Your healthcare provider will contact you to review the results and discuss any next steps.
After all blood samples are collected, you can resume your normal activities. You may experience mild bruising or soreness at the injection sites. The blood samples will be sent to a laboratory for analysis. Your doctor will discuss the results with you at a follow-up appointment, explaining what the levels mean for your health.
Reference range
Baseline (pre-ACTH): 0.2-3.0 ng/mL; Post-ACTH stimulation (60 min): 10-30 ng/mL; Peak response (6th specimen): 15-50 ng/mL. Reference ranges vary by laboratory methodology and assay kit.N/A
Patient should fast overnight (8-12 hours). Basal specimen collected between 6:00-8:00 AM. ACTH (cosyntropin) administered intravenously or intramuscularly at standard dose. Serial blood samples collected at timed intervals (30, 60, 90, 120 minutes and subsequent specimens). Avoid glucocorticoids and adrenal hormone medications prior to testing if clinically feasible.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
The 17-OHP test after ACTH stimulation helps diagnose several conditions. Elevated 17-OHP levels after stimulation may indicate congenital adrenal hyperplasia (CAH), a genetic disorder affecting adrenal hormone production. Normal response to ACTH stimulation shows a moderate increase in 17-OHP levels. Abnormally low or absent response may suggest adrenal insufficiency (Addison's disease) or pituitary gland problems. The test can also help identify adrenal tumors and evaluate adrenal gland function before starting certain treatments.
Frequently asked questions
Is the ACTH stimulation test painful?
How long does the entire test take?
Are there any side effects from the ACTH injection?
What do abnormal results mean?
Do I need to stop my medications before this test?
Sources
- 1
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- 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