Prolactin (Serum)
This test measures the amount of prolactin, a hormone produced by the pituitary gland, in your blood. Prolactin helps regulate breast milk production and affects other body functions, including mood and sleep.
["Prolactin helps regulate breast milk and influences mood, sleep, and other bodily functions."]
Key facts at a glance
- LOINC
- 12231-7
- Short code
- Prolactin BS SerPl-mCnc
- Synonyms
- Prolactin BS SerPl-mCnc
- 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 Is This Test Done?
Your healthcare provider may order a prolactin test to check for hormonal imbalances, evaluate symptoms like breast changes, irregular menstrual periods, infertility, or unexplained headaches. It can also help diagnose conditions such as pituitary tumors or thyroid disorders.
What to Expect Before the Test
No special preparation is usually needed. You may be asked to fast for 8–12 hours before the test if your blood is drawn early in the morning, as prolactin levels can vary throughout the day. Avoid smoking or caffeine before the test.
What Happens During the Test?
A healthcare professional will draw blood from a vein in your arm. You may feel a slight pinch, but the procedure is quick and typically painless. The blood sample will be sent to a lab for analysis.
What Are Possible Results?
Results are interpreted based on your health, symptoms, and medical history. High prolactin levels may suggest conditions like a pituitary tumor, thyroid issues, or certain medications. Low levels could indicate rare hormonal deficiencies.
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.
Clinical Significance: High prolactin levels may cause infertility, menstrual irregularities, breast changes, or headaches. Low levels are less common but may signal underlying hormonal imbalances. Always discuss results with your provider for personalized guidance.
Short name
Prolactin Level
Frequently asked questions
What causes prolactin levels to be abnormally high?
How long does it take to get prolactin test results?
Can prolactin levels change with stress or activity?
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