Serum Prolactin Level with 1-Hour Post-RhGH Stimulation (Human Growth Hormone)
This test measures your prolactin hormone level before and after a small dose of growth hormone (rhGH). It helps doctors check how well your pituitary gland responds to stimulation.
["Assesses pituitary function and hormone balance after a growth hormone challenge."]
Key facts at a glance
- LOINC
- 44925-6
- Short code
- Prolactin 1h p TRH IV SerPl-aCnc
- Synonyms
- Prolactin 1h p TRH IV SerPl-aCnc
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 0.8
- Ref high
- 1.2
- Critical range
- — – 5 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 85610
- SNOMED
- 396252006
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
Why This Test Is Done
Your doctor may order this test if you have symptoms like unexplained weight changes, fatigue, or signs of hormone imbalance. It’s also used to evaluate pituitary gland function, especially after trauma, surgery, or radiation therapy to the head.
What to Expect Before the Test
You’ll fast for 8–12 hours before the test. Bring your medications and let your doctor know if you’re pregnant, breastfeeding, or have allergies. Avoid caffeine or alcohol before testing.
The Testing Process
A blood sample is drawn from a vein (usually in your arm) before and 1 hour after receiving a small dose of growth hormone. The test measures prolactin levels at both time points to see how your body reacts.
What the Results Mean
Results help doctors diagnose conditions like pituitary tumors, hyperprolactinemia, or growth hormone deficiencies. Abnormal results may require further testing or treatment plans.
Reference range
INR: 0.8-1.2 (warfarin: 2.0-3.0)N/A
Inform your healthcare provider if you are taking blood thinners. No special preparation required.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
High prolactin levels after stimulation may indicate a pituitary tumor or other issues blocking hormone production. Low prolactin or abnormal growth hormone responses could signal pituitary dysfunction, which may affect metabolism, growth, or reproductive health. This test is critical for diagnosing and managing hormonal imbalances.
Short name
Prolactin + Growth Hormone Stim Test
Frequently asked questions
How long does the test take?
Can I eat or drink anything before the test?
Will I feel any pain or discomfort during the blood draw?
Sources
- 1
- 2Lab Tests OnlineSource
- 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 16, 2026. · Read our editorial policy