Complete Blood Count (CBC)
A blood test measuring 17-hydroxyprogesterone levels after a hormone stimulation test to evaluate adrenal gland function.
{"This test checks how your adrenal glands respond to hormone stimulation","It helps diagnose conditions like congenital adrenal hyperplasia (CAH) and adrenal insufficiency","Multiple blood samples are taken over several hours after receiving a stimulating hormone","Elevated 17-OHP levels may indicate adrenal hormone production problems","The test is typically performed in the morning after overnight fasting"}
Key facts at a glance
- LOINC
- 57535-7
- Short code
- 17OHPSTIM
- Synonyms
- 17OHP sp12 p chal SerPl-mCnc
- Category
- chemistry
- Sample
- serum
- Container
- Serum Separator Tube (SST) or Plain Red Top Tube
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- ≥ 0 years
- Method
- Chemiluminescent Immunoassay (CLIA) or Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
- CPT
- 82533
- SNOMED
- 31315003
- Specimen volume
- 1.0-2.0 mL serum
- 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
The complete blood count, or CBC, is a common blood test that measures the different cells in your blood, including red blood cells, white blood cells, and platelets, giving your doctor a clear picture of your overall health.
The 17-Hydroxyprogesterone (17-OHP) test measures the amount of 17-hydroxyprogesterone in your blood. This test is performed after you receive a hormone challenge (typically synthetic ACTH/cortrosyn) to stimulate your adrenal glands. The 12th specimen refers to multiple blood samples collected over time—usually every 30-60 minutes for several hours—to track how your adrenal glands respond to stimulation.
This test is performed to check for a wide range of conditions, such as anemia, infections, and blood clotting problems, to investigate symptoms like fatigue, weakness, or fever, and to monitor how well a treatment or chronic condition is being managed.
This test is primarily used to diagnose and evaluate: (1) Congenital Adrenal Hyperplasia (CAH) - a genetic condition affecting adrenal hormone production, (2) Adrenal insufficiency (Addison's disease) - when adrenal glands don't produce enough hormones, and (3) Other disorders of steroid hormone metabolism. The stimulation test helps doctors see if your adrenal glands can properly respond to stress signals.
In most cases, no special preparation is needed, and you can eat and drink normally before the test. However, if the CBC is ordered together with other blood tests, your doctor may ask you to fast for several hours, so be sure to follow any instructions you are given.
Follow these preparations: (1) Fast overnight (usually 8-12 hours) before the test, (2) Inform your doctor about all medications you're taking, as some drugs can affect results, (3) Discuss any existing medical conditions, especially adrenal or pituitary disorders, (4) Wear comfortable clothing as you'll have multiple blood draws, (5) The test may take 2-4 hours or longer, so plan accordingly.
A healthcare professional will wrap a band around your upper arm, clean the skin, and draw a small sample of blood from a vein, usually in your arm. The sample is then sent to a laboratory for analysis, and the entire process typically takes only a few minutes.
First, a baseline blood sample is taken. Then you'll receive an injection of synthetic ACTH (cortrosyn) to stimulate your adrenal glands. Additional blood samples will be drawn at specific intervals (the 12th specimen means multiple samples over time). Each sample measures how your 17-OHP levels change in response to the stimulation. The healthcare team will monitor you throughout the procedure.
Reference range
Reference range for ACTH-stimulated 17-Hydroxyprogesterone varies by protocol and laboratory; baseline and post-stimulation values are interpreted together. Contact laboratory for protocol-specific ranges.N/A
No fasting required. Inform the laboratory of current medications, especially corticosteroids or hormonal contraceptives. For ACTH stimulation test, follow stimulation protocol instructions regarding pre-test medications.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
**Elevated 17-OHP levels** after ACTH stimulation strongly suggest congenital adrenal hyperplasia (CAH), specifically 21-hydroxylase deficiency. The severity helps classify CAH (classical vs. non-classical). In adults, mildly elevated levels may indicate late-onset CAH.
**Low or blunted 17-OHP response** may indicate adrenal insufficiency or poor pituitary function. This helps differentiate between primary adrenal failure and secondary adrenal insufficiency caused by pituitary problems.
**Normal response** after stimulation suggests normal adrenal function. However, results should always be interpreted by your healthcare provider in context with your symptoms and other test results.
Frequently asked questions
Does the ACTH stimulation test have side effects?
How long does the entire test take?
When will I get my results?
Are there any medications I should avoid before the test?
Is this test painful?
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