Understanding Your Medical Test: A Complete Patient Guide
A blood test that measures 17-hydroxyprogesterone levels to evaluate how well dexamethasone treatment is controlling congenital adrenal hyperplasia.
{"This test measures the hormone 17-hydroxyprogesterone in your blood","It is taken 2 days after your dexamethasone dose to check treatment effectiveness","The test helps doctors monitor whether your medication is properly suppressing excess hormone production","Abnormal results may indicate that your treatment needs adjustment","The test requires a simple blood draw from your arm"}
Key facts at a glance
- LOINC
- 57550-6
- Short code
- 17-OHP-DX
- Synonyms
- 17OHP 2D p Dex SerPl-sCnc
- Category
- chemistry
- Sample
- serum
- Container
- Serum separator tube (SST/gold top) or red top plain tube
- Units
- N/A
- Ref low
- 0.006
- Ref high
- 0.06
- Critical range
- — – 0.45 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 0–120 years
- Method
- Chemiluminescence Immunoassay (CLIA) or Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
- CPT
- 83498
- SNOMED
- 31316005
- 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
- 40
- TAT
- 24–72 hours
- Order
- routine
What is this test and what is it used for?
The 17-Hydroxyprogesterone (17-OHP) test measures the amount of this hormone in your blood. This test is specifically performed 2 days after taking a dose of dexamethasone, a medication used to treat certain adrenal gland disorders. The '2 days post dose' timing is important because it helps doctors understand how well your medication is suppressing the production of 17-OHP, which is often elevated in conditions like congenital adrenal hyperplasia (CAH).
Why do I need this test and what will it show my doctor?
Your doctor has ordered this test to monitor how effectively your dexamethasone treatment is working. In conditions like congenital adrenal hyperplasia, the adrenal glands produce too much 17-OHP. Dexamethasone helps suppress this overproduction. By measuring your 17-OHP level 2 days after taking your medication, your doctor can determine if your current treatment dose is appropriate or needs adjustment.
How should I prepare for this test before my appointment?
Follow your doctor's instructions regarding your dexamethasone dose. The timing of your blood draw is critical - it must be exactly 2 days after your dexamethasone dose. Your doctor will tell you exactly when to take your medication and when to have your blood drawn. Generally, you may continue your normal activities and eat a normal diet before the test unless your doctor instructs otherwise.
What happens during the test and how long does it take?
A healthcare professional will draw a small sample of blood from a vein in your arm using a needle. You may feel a brief pinch or sting. The blood sample will be sent to a laboratory for analysis. The test itself is quick, usually taking only a few minutes.
What do my test results mean for my health and care plan?
Your test results will show whether your 17-OHP level has been adequately suppressed by your dexamethasone treatment. Low or normal 17-OHP levels after dexamethasone suggest your treatment is working well. High levels may indicate that your medication dose needs adjustment. Your doctor will interpret your results in the context of your overall health and treatment plan.
Reference range
Adults without CAH: 0.2-2.0 ng/mL (0.006-0.060 nmol/L). For CAH monitoring on dexamethasone: Target <1.0 ng/mL. Neonates: Reference ranges vary significantly by age. Interpretation should consider clinical context, age, and sex.N/A
No fasting required. Specimen should be collected 2 days after dexamethasone dose as specifically ordered. For females, note menstrual cycle phase as 17-OHP may vary throughout cycle. Inform laboratory of any steroid medications or hormonal contraceptives.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Frequently asked questions
Why does the blood draw need to be exactly 2 days after my dexamethasone dose?
Will I feel any pain during the test?
What happens if my 17-OHP levels are still high?
Are there any side effects from this test?
How often will I need this test?
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