Understanding Your Laboratory Test: Purpose, Procedure, and What the Results Mean
A blood test measuring 17-hydroxyprogesterone levels, collected after gonadotropin-releasing hormone (GnRH) stimulation to evaluate adrenal gland function.
{"Measures hormone levels to check adrenal gland function","Helps diagnose conditions like congenital adrenal hyperplasia (CAH)","Blood sample is taken multiple times after GnRH injection","Used mainly in children and adults with hormone-related symptoms","Results help doctors plan appropriate treatment"}
Key facts at a glance
- LOINC
- 57542-3
- Short code
- 17-OHP
- Synonyms
- 17OHP sp5 p GnRH SerPl-mCnc
- Category
- chemistry
- Sample
- serum
- Container
- Serum Separator Tube (SST) or Plain Red Top Tube
- Units
- N/A
- Ref low
- 2
- Ref high
- 30
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 0–18 years
- Method
- Immunoassay (Chemiluminescence or Enzyme-Linked Immunosorbent Assay)
- CPT
- 83498
- SNOMED
- 31327005
- Specimen volume
- 1.0-2.0 mL of 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
This test is a laboratory procedure that helps your healthcare provider gather important information about your health. It is commonly ordered as part of a routine checkup or to investigate specific symptoms, and it provides valuable data that guides diagnosis and treatment decisions.
The 17-Hydroxyprogesterone (17-OHP) test measures the amount of a hormone called 17-hydroxyprogesterone in your blood. This hormone is produced by the adrenal glands, which sit on top of your kidneys. The test is performed after receiving an injection of gonadotropin-releasing hormone (GnRH), which stimulates the adrenal glands to produce hormones. Blood samples are collected at specific intervals, with the '5th specimen' referring to the fifth blood draw after the GnRH dose.
This test is performed to help your doctor evaluate how well your body is functioning, screen for potential health conditions, monitor an existing diagnosis, or check how well a current treatment is working. Your provider will order it based on your symptoms, medical history, and overall health needs.
This test is primarily used to evaluate how well your adrenal glands are functioning. It helps doctors diagnose conditions such as congenital adrenal hyperplasia (CAH), a genetic disorder affecting hormone production in the adrenal glands. The GnRH stimulation test helps show how your body responds to hormonal signals and whether your adrenal glands produce hormones normally.
The test is usually performed by collecting a small sample, such as blood or urine, at a clinic, hospital, or laboratory. A trained professional gathers the sample and sends it to a lab for analysis. The procedure is typically quick, and you can usually return to your normal activities right away.
A healthcare professional will first give you an injection of GnRH. Then, they will draw several blood samples over a period of time—typically at 15, 30, 60, and 90 minutes after the injection. The 5th specimen mentioned in the test name refers to one of these timed blood draws. The blood samples are sent to a laboratory where the 17-OHP levels are measured.
Your results show whether your values fall within the normal range for this test. Normal results generally suggest no cause for concern, while abnormal results may point to a condition that requires further evaluation. Your healthcare provider will review the findings with you, explain what they mean, and discuss any recommended next steps.
Normal 17-OHP levels vary by age and gender. High levels of 17-OHP may indicate congenital adrenal hyperplasia (CAH) or other adrenal gland disorders. Your doctor will interpret your results based on your age, symptoms, and medical history. Additional tests may be needed to confirm a diagnosis.
Reference range
Reference ranges for 17-Hydroxyprogesterone following GnRH stimulation vary significantly by age, sex, and pubertal stage. In children, peak response values typically range from 2-10 ng/dL (0.06-0.30 nmol/L) in prepubertal children, while pubertal values may reach 10-30 ng/dL (0.30-0.90 nmol/L). Specific reference ranges should be interpreted based on the clinical context and laboratory-specific standards.N/A
This is the 5th specimen collected following gonadotropin releasing hormone (GnRH) administration as part of a GnRH stimulation test. The patient should rest for 30 minutes prior to testing. No fasting is required, but avoiding strenuous exercise is recommended. Inform the laboratory of any medications, particularly corticosteroids or hormonal contraceptives, that may affect results.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
The 17-OHP test after GnRH stimulation is primarily used to diagnose and monitor congenital adrenal hyperplasia (CAH), a condition where the adrenal glands produce abnormal amounts of hormones. It can also help evaluate adrenal insufficiency, adrenal tumors, and certain types of puberty disorders. In children, this test is crucial for identifying CAH early, as early diagnosis and treatment can prevent serious complications. The GnRH stimulation aspect of this test helps distinguish between different types of hormonal disorders by showing how the adrenal glands react to hormonal stimulation.
Frequently asked questions
Does the GnRH injection cause any side effects?
How should I prepare for this test?
Are there any risks associated with this test?
When will I get my results?
What happens if my results are abnormal?
Sources
- 1
- 2
- 3
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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