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Prolactin level measured via immunoassay (serum/plasma)

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

This test checks the amount of prolactin, a hormone produced by your pituitary gland, in your blood. Prolactin helps regulate milk production and affects other body functions like mood and sleep.

Quick summary

["Prolactin helps regulate milk production and influences mood, sleep, and other bodily functions."]

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

Key facts at a glance

LOINC
47869-3
Short code
Prolactin 1h p MCP SerPl-aCnc
Synonyms
Prolactin 1h p MCP SerPl-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
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 investigate symptoms such as unusual breast milk production, infertility, irregular menstrual cycles, headaches, or signs of hormonal imbalances. It can also help diagnose conditions like pituitary tumors or other hormonal disorders.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to fast for 8–12 hours before the test if instructed. Bring any medications you’re currently taking, as some can affect results.

What Happens During the Test?

A healthcare provider will draw blood from a vein in your arm. You may feel a slight pinch, but the process is quick and typically painless. The sample is then sent to a lab for analysis.

What Are Possible Results?

Results are compared to a general reference range, but individual ranges can vary by lab. High prolactin levels may suggest conditions like pituitary tumors, thyroid issues, or certain medications. Low levels could indicate problems with hormone production or pituitary dysfunction.

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

Short name

Prolactin

Frequently asked questions

What Does a High Prolactin Level Mean?
Elevated prolactin can cause symptoms like missed periods, infertility, breast tenderness, or galactorrhea (milk leakage). It may also lead to fatigue, headaches, or vision changes. Conditions like pituitary adenomas (benign tumors) or thyroid disorders can cause elevated levels.
What Does a Low Prolactin Level Mean?
Low prolactin might indicate problems with the pituitary gland or hypothalamus, which control hormone release. Rarely, it could be linked to genetic disorders or certain medications. Symptoms may include infertility, irregular periods, or low libido.
How Often Should I Get This Test?
Your doctor will determine how often you need retests based on your symptoms, medical history, and treatment plan. Follow-up may be needed if you’re taking medications that affect prolactin levels or if you’re experiencing ongoing hormonal issues.
  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