Prolactin Serum Concentration (2-Hour Post-TRH Stimulation)
This test measures your prolactin hormone level after a specific trigger to help diagnose conditions affecting hormone production or regulation in the pituitary gland.
["Assesses how your body responds to a hormone-stimulating challenge to check for potential pituitary or thyroid issues."]
Key facts at a glance
- LOINC
- 47731-5
- Short code
- Prolactin 2h p TRH IV SerPl-mCnc
- Synonyms
- Prolactin 2h p TRH IV SerPl-mCnc
- 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 infertility, irregular menstrual periods, high or low hormone levels, or signs of a pituitary tumor. It can also help evaluate conditions like hyperprolactinemia or hypothyroidism.
What to Expect Before the Test
No special preparation is needed, but you may be asked to fast for 8 hours before the test. Your blood will be drawn from a vein in your arm after you’ve received a small dose of thyrotropin-releasing hormone (TRH) to stimulate hormone release.
What Happens During the Test
A healthcare provider will insert a small needle into your arm to draw blood at two time points: before and 2 hours after TRH administration. The blood sample is sent to a lab for analysis of prolactin hormone concentration.
What the Results Mean
Results help determine if your prolactin levels are elevated or appropriately stimulated by TRH, which can indicate issues with hormone production, pituitary function, or other endocrine disorders.
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.
Elevated prolactin levels after TRH stimulation may suggest a pituitary tumor, thyroid dysfunction, or other conditions affecting hormone regulation. Low or abnormal responses could indicate pituitary dysfunction or other underlying health concerns that need further evaluation.
Short name
Prolactin Test (TRH-Stimulated)
Frequently asked questions
What causes prolactin levels to be tested?
How long does it take to get results?
Can I eat or drink before this test?
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