Skip to content

Serum Prolactin Level

Published: August 9, 2026Updated: August 16, 2026

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 bodily functions.

Quick summary

["Prolactin levels can help diagnose hormonal imbalances or conditions affecting the pituitary gland."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
25740-2
Short code
Prolactin 40M p 200 ug TRH IV SerPl-mCnc
Synonyms
Prolactin 40M p 200 ug TRH IV 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 This Test Might Be Ordered

Your healthcare provider may recommend a prolactin test if you have symptoms like unexplained breast milk production in men, irregular menstrual periods, infertility, headaches, or vision changes. It may also be checked during evaluations for pituitary tumors or other hormonal disorders.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to avoid certain medications (like birth control pills or certain antidepressants) that can affect prolactin levels. If you’re breastfeeding, let your provider know—this can influence results.

During the Test

A blood sample will be drawn from a vein, typically in your arm. You may feel a slight pinch, but it’s quick and usually not painful. The sample is sent to a lab for analysis.

What the Results Mean

Results help determine if your prolactin levels are within the normal range or if they’re too high or low. Abnormal levels may signal conditions like pituitary tumors, thyroid issues, or other hormonal imbalances.

Reference range

Adult males: 2-18 ng/mL; Females: 2-29 ng/mLN/A

Specimen: serum

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: Prolactin Levels and Health

Short name

Prolactin

Frequently asked questions

What causes high prolactin levels?
High prolactin can be caused by tumors in the pituitary gland, certain medications (like antipsychotics or birth control), kidney or liver disease, or conditions like hyperprolactinemia. Low prolactin may result from pituitary damage, thyroid disorders, or genetic factors.
How does prolactin affect pregnancy?
Prolactin plays a key role in lactation. High levels may interfere with ovulation or pregnancy, while low levels could affect milk production if you’re breastfeeding. Always discuss results with your provider, especially if you’re planning to conceive or breastfeed.
Can diet or lifestyle affect prolactin levels?
While diet and lifestyle factors like stress or sleep quality may influence hormone balance indirectly, they don’t directly alter prolactin levels. Stick to your provider’s instructions regarding medications or timing of the test for accurate results.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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