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Prolactin, Serum

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

This test measures the amount of prolactin, a hormone produced by your 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
2841-5
Short code
Prolactin Smn-mCnc
Synonyms
Prolactin Smn-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 doctor may order a prolactin test to check for conditions like hyperprolactinemia (too much prolactin), pituitary tumors, or issues with hormone production. It can also help evaluate symptoms such as missed periods, infertility, or unusual breast milk production in men.

What to Expect Before the Test

No special preparation is needed, but you may be asked to fast for 8–12 hours before the test if your blood is drawn early in the morning. Wear comfortable clothing and plan to stay near the testing site for about 15 minutes.

What Happens During the Test?

A healthcare provider will insert a small needle into a vein in your arm or hand to draw blood. You may feel a slight pinch, but the process is quick. The blood sample is then sent to a lab for analysis.

What Are Possible Results?

Results are expressed in nanograms per deciliter (ng/dL) or micrograms per liter (µg/L). Your doctor will compare your results to a reference range specific to your age, sex, and health status to determine if further action is needed.

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

How long does it take to get prolactin test results?
Results are typically available within 1–3 business days, depending on your lab’s processing time. Your doctor will contact you once they’re ready to review them.
Can I take anything by mouth before the test?
If your blood is drawn in the morning, avoid eating or drinking (except water) for 8–12 hours before the test. If your doctor has different instructions, follow those instead.
Does stress affect prolactin levels?
Yes, stress, exercise, or certain medications (like birth control pills) can temporarily raise prolactin levels. Your doctor may recommend retesting if your results seem unusually high or low due to recent stress or medication 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