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Serum Prolactin Concentration by Immunoassay

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.

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
33906-9
Short code
Prolactin 30M p 200 ug TRH IV SerPl-sCnc
Synonyms
Prolactin 30M p 200 ug TRH IV SerPl-sCnc
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 Might You Need This Test?

Your doctor may order this test if you have symptoms like unexplained breast milk production in men, irregular menstrual periods, infertility, or signs of a pituitary tumor. It can also be part of evaluating conditions like hyperprolactinemia or hypothyroidism.

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 your doctor specifies it. Wear comfortable clothing for blood draw.

What Happens During the Test?

A healthcare professional will draw blood from a vein in your arm. You may feel a slight pinch, but it’s usually over quickly. The blood sample is then sent to a lab for analysis.

What Are Possible Results?

Results are reported as a concentration of prolactin in nanograms per milliliter (ng/mL). Your doctor will compare these results to your individual reference range and medical history to interpret them.

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.

Elevated prolactin levels may indicate conditions like a pituitary tumor, kidney disease, or certain medications (e.g., antidepressants). Low levels could suggest pituitary damage or thyroid issues. Always discuss results with your doctor for personalized guidance.

Short name

Prolactin Level

Frequently asked questions

What causes prolactin levels to be abnormally high?
High prolactin levels can result from pituitary tumors, kidney problems, certain medications (like antidepressants or antipsychotics), pregnancy, or stress. Lifestyle factors like caffeine or smoking may also play a role.
How often should I get this test?
Your doctor will determine how often you need this test based on your symptoms, medical history, and treatment plan. Follow-up tests may be scheduled if your levels are abnormal or if you’re managing a condition like hyperprolactinemia.
Can diet or lifestyle changes affect prolactin levels?
Yes, factors like caffeine, alcohol, and smoking can temporarily raise prolactin levels. Stress, exercise, and certain medications also influence results. Avoiding these triggers before your test may give a more accurate reading.
  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