Complete Blood Count (CBC) Test: What Patients Should Know
A blood test measuring 17-hydroxyprogesterone levels to evaluate adrenal gland function and screen for congenital adrenal hyperplasia.
{"Measures hormone levels before an ACTH stimulation test","Helps diagnose adrenal gland disorders like congenital adrenal hyperplasia (CAH)","Involves a blood draw from a vein in your arm","Results help doctors assess if your adrenal glands are functioning properly","May be ordered for infants, children, or adults with hormone-related symptoms"}
Key facts at a glance
- LOINC
- 61174-9
- Short code
- 17-OHPret
- Synonyms
- 17OHP 20M pre chal SerPl-sCnc
- Category
- chemistry
- Sample
- serum
- Container
- Serum Separator Tube (SST/Gold top) or Plain Red Top Tube
- Units
- N/A
- Ref low
- 10
- Ref high
- 200
- Critical range
- — – 10000 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 0–120 years
- Method
- Chemiluminescent Immunoassay (CLIA) or Enzyme-Linked Immunosorbent Assay (ELISA)
- CPT
- 83498
- SNOMED
- 31318009
- 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
What is a complete blood count (CBC) test?
The 17-Hydroxyprogesterone (17-OHP) test measures the amount of 17-hydroxyprogesterone in your blood. This hormone is produced by the adrenal glands and is a precursor to cortisol, the body's main stress hormone. The test is performed 20 minutes before an ACTH (adrenocorticotropic hormone) stimulation challenge, which helps doctors evaluate how well your adrenal glands are working.
Why is a complete blood count (CBC) test performed?
This test is primarily used to screen for and diagnose congenital adrenal hyperplasia (CAH), a genetic condition that affects the adrenal glands' ability to produce cortisol and sometimes aldosterone. It may also be used to evaluate adrenal tumors or assess adrenal gland function in patients with symptoms of hormone imbalance.
Most people do not need any special preparation for this test, and you can usually eat and drink normally before your appointment. Tell the person drawing your blood about any medicines you take, especially blood thinners, and mention if you have felt faint during past blood draws or have hard-to-find veins.
Follow your healthcare provider's instructions carefully. 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 drugs can affect hormone levels. The test is typically done in the morning when hormone levels are most stable.
A nurse or phlebotomist will wrap a band around your upper arm, clean the inside of your elbow with an antiseptic, and insert a small needle to collect one or two tubes of blood. The draw usually takes less than five minutes, and you may feel a brief sting. Afterward, a cotton pad and bandage are applied, and you can return to your normal activities right away.
A healthcare professional will draw blood from a vein in your arm using a small needle. You may feel a brief pinch or sting. The blood sample will be collected in a tube and sent to a laboratory for analysis. The entire process takes only a few minutes.
Your report will show counts of red blood cells, white blood cells, and platelets, along with hemoglobin and hematocrit values and a reference range for each result. A value slightly outside the normal range does not always mean illness, so your doctor will consider your symptoms and medical history as well. Ask your provider to explain any result you do not understand and whether follow-up testing is needed.
Normal results vary based on age, sex, and pregnancy status. Your doctor will interpret your results in context with your symptoms and other test findings. Elevated 17-OHP levels may indicate congenital adrenal hyperplasia or adrenal tumors, while low levels might suggest adrenal insufficiency. Your healthcare provider will discuss what your specific results mean for your health.
Reference range
Baseline (pre-ACTH challenge): <200 ng/dL (6 nmol/L) is considered normal. Levels >1000 ng/dL (30 nmol/L) highly suggestive of 21-hydroxylase deficiency congenital adrenal hyperplasia. Reference ranges may vary by laboratory and assay methodology.N/A
No fasting required. Inform patient that this is a baseline sample collected 20 minutes prior to ACTH (cosyntropin) stimulation test. Collect in morning hours due to circadian rhythm of adrenal hormones. Document current medications, especially corticosteroids or hormonal contraceptives.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
The 17-OHP test is crucial for diagnosing congenital adrenal hyperplasia (CAH), a group of genetic disorders affecting adrenal hormone production. Early detection and treatment of CAH is essential to prevent complications such as ambiguous genitalia in females, early puberty, rapid growth followed by short stature, and adrenal crisis. The test is also valuable in evaluating adrenal tumor involvement and monitoring treatment effectiveness in patients with adrenal disorders.
Frequently asked questions
Is the test painful?
How long does it take to get results?
Do I need to fast before the test?
What happens after the ACTH stimulation challenge?
Can medications affect my test results?
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