Prolactin Isoforms (Serum)
This test measures different forms of prolactin, a hormone produced by the pituitary gland, in your blood. It helps assess how your body is processing and utilizing this hormone.
["Understanding your prolactin isoforms may help diagnose hormonal imbalances or conditions affecting hormone metabolism."]
Key facts at a glance
- LOINC
- 78993-3
- Short code
- Prolactin isoforms Pnl SerPl
- Synonyms
- Prolactin isoforms Pnl SerPl
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 2
- Ref high
- 18
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 84146
- 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 Might Be Ordered
Your healthcare provider may recommend this test if you have symptoms like unusual breast milk production (galactorrhea), menstrual irregularities, headaches, or signs of hormonal imbalances. It may also be used to evaluate pituitary gland function or to investigate unexplained infertility.
What to Expect Before the Test
No special preparation is typically needed. You may have a small needle inserted into a vein in your arm to draw blood. If you’re taking medications that affect prolactin levels, let your provider know.
How the Test Results Are Used
Results help determine if your prolactin levels are within normal ranges or if there are variations in specific prolactin isoforms that might indicate underlying health concerns. This can guide treatment decisions.
Common Conditions This Test May Help Identify
This test may be used to investigate conditions such as hyperprolactinemia (elevated prolactin), pituitary tumors, or other hormonal disorders that can affect prolactin metabolism.
Reference range
Adult males: 2-18 ng/mL; Females: 2-29 ng/mLN/A
For females: inform if menstrual cycle status. For certain tests, timing within menstrual cycle may matter.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
While standard prolactin tests measure total hormone levels, isoform-specific testing can provide additional detail. Variations in prolactin isoforms may suggest issues with hormone processing, such as liver or kidney dysfunction, or other metabolic conditions that affect protein breakdown or synthesis.
Short name
Prolactin Isoform Profile
Frequently asked questions
What does a prolactin isoform test measure?
How long does it take to get results from this test?
Can lifestyle changes affect prolactin isoform levels?
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