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Prolactin Serum Concentration

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 milk production in women and influences other bodily functions, including mood and sleep.

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
20434-7
Short code
Prolactin SerPl 3rd IS-aCnc
Synonyms
Prolactin SerPl 3rd IS-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
rd-is
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 other hormonal disorders. It might also be used to monitor treatment for conditions like thyroid disease or breast cancer.

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 by your healthcare provider. Wear comfortable clothing and plan to stay near the testing site for a short time.

What Happens During the Test?

A healthcare professional will draw blood from a vein in your arm using a small needle. You may feel a slight sting, but it usually doesn’t cause significant discomfort. The blood sample will be sent to a lab for analysis.

What Are Possible Results?

Results are compared to standard reference ranges, but your actual values will depend on lab-specific guidelines. High prolactin levels may indicate issues like tumors or medications affecting hormone production, while low levels might suggest 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 Level

Frequently asked questions

What Does It Mean If My Results Are Abnormal?
High prolactin levels can cause symptoms like missed periods (in women), infertility, or galactorrhea (milk production outside breastfeeding). In men, it may lead to erectile dysfunction or reduced sperm count. Low levels might suggest problems with hormone regulation or pituitary gland function.
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 tests may be scheduled if your results are outside the normal range or if you’re undergoing treatment for a condition linked to prolactin.
Can I Take Anything Before or After the Test?
You can typically eat and drink normally unless your doctor specifies otherwise. Avoid smoking or consuming caffeine for at least 30 minutes before the test, as it may affect results. Follow-up instructions will be provided by your healthcare team.
  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