Skip to content

Prolactin, Serum (Chemiluminescent Immunoassay)

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

This test measures the level of prolactin, a hormone produced by the pituitary gland that plays a key role in milk production and regulates certain reproductive functions.

Quick summary

["Prolactin levels 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
12826-4
Short code
Prolactin sp5 p chal SerPl-mCnc
Synonyms
Prolactin sp5 p chal 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 doctor may order this test if you have symptoms like irregular menstrual cycles, infertility, breast changes, or signs of a pituitary tumor. It can also be checked during evaluations for hyperprolactinemia (high prolactin levels) or hypoprolactinemia (low prolactin levels).

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to avoid certain medications that could affect results. If you’re breastfeeding, let your doctor know, as it may influence interpretation.

How the Test Is Performed

A blood sample is drawn from a vein, typically in your arm. The sample is sent to a lab for analysis using a chemiluminescent immunoassay method to detect prolactin levels.

Possible Results and Their Meaning

Results are compared to a reference range, but individual needs vary. High levels may suggest conditions like pituitary tumors, thyroid issues, or certain medications. Low levels might indicate pituitary dysfunction or pregnancy.

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 Can Reflect Underlying Health Conditions

Short name

Serum Prolactin

Frequently asked questions

What Are Common Causes of Abnormal Results?
High prolactin levels can be caused by tumors in the pituitary gland, certain medications (like antipsychotics or birth control), kidney disease, or thyroid disorders. Low levels may result from pituitary damage, pregnancy, or genetic conditions.
How Often Should This Test Be Repeated?
Your doctor will determine follow-up frequency based on your symptoms and test results. Repeat testing may be needed if initial results are abnormal or if symptoms persist.
Can Diet or Lifestyle Affect Prolactin Levels?
While diet and stress can influence hormone levels indirectly, they do not directly alter prolactin measurements. Avoiding caffeine or alcohol before testing may help ensure 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