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Prolactin (Serum)

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 body functions, including reproduction and mood.

Quick summary

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

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

Key facts at a glance

LOINC
83111-5
Short code
Prolactin SerPl IA-aCnc
Synonyms
Prolactin SerPl IA-aCnc
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
Method
ia
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 irregular menstrual periods, infertility, breast tenderness, high or low blood pressure, headaches, or unexplained weight changes. It may also be checked in cases of suspected pituitary tumors or other hormonal disorders.

What to Expect Before the Test

No special preparation is usually needed. You may be asked to fast for a few hours before the blood draw, but this depends on your provider’s instructions. Wear comfortable clothing and plan to stay near the testing site for a short time.

How the Test Is Performed

A healthcare professional will insert a needle into a vein in your arm to draw blood. You may feel a slight sting, but it usually doesn’t cause much discomfort. The blood sample is then sent to a lab for analysis.

What the Results Mean

Results are compared to a reference range, which can vary by lab. High prolactin levels may indicate conditions like pituitary tumors, thyroid issues, or certain medications. Low levels might suggest rare pituitary problems or other hormonal imbalances. Your provider will discuss these findings with you.

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.

◆Associated findings1

Short name

Prolactin Level

Frequently asked questions

What causes high prolactin levels?
High prolactin levels can result from conditions like pituitary adenomas (benign tumors), thyroid disorders, kidney problems, or certain medications (e.g., antidepressants, antipsychotics). Stress, pregnancy, or breastfeeding can also temporarily raise prolactin.
What causes low prolactin levels?
Low prolactin levels are less common and may be linked to rare pituitary issues, genetic disorders, or severe medical conditions. Some medications or hormonal imbalances can also affect production.
How often should I get this test?
Your provider will determine how often to repeat this test based on your symptoms, medical history, and test results. Follow-up may be needed if initial results are abnormal or if your condition changes.
  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