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Prolactin (Serum or Plasma) by High-Performance Liquid Chromatography (HPLC)

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

This test measures the amount of prolactin, a hormone produced by the pituitary gland, in your blood. Prolactin helps regulate breastfeeding and affects other body functions like mood and reproduction.

Quick summary

["Prolactin levels can 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
16109-1
Short code
Prolactin 2h p chal SerPl-mCnc
Synonyms
Prolactin 2h 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 healthcare provider may order a prolactin test to check for conditions like hyperprolactinemia (high prolactin levels), which can cause issues with fertility, irregular menstrual cycles, or breast milk production. It may also be used to evaluate symptoms such as headaches, vision problems, or unexplained galactorrhea (milk discharge from nipples).

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 blood is drawn in the morning. Tell your provider about any medications, supplements, or recent stress or exercise that could affect results. Avoid smoking or caffeine before testing if advised by your doctor.

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 brief pinch, but it usually doesn’t cause significant discomfort. The blood sample is then sent to a lab for analysis using HPLC to measure prolactin concentration.

What Do Results Mean?

Results are interpreted by your provider based on your symptoms, medical history, and other test results. High prolactin levels may indicate pituitary tumors, thyroid issues, or certain medications. Low levels could suggest pituitary damage or other hormonal imbalances. Reference ranges vary by lab, so your provider will discuss what your specific result means for you.

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

What Are Common Causes of Abnormal Results?
High prolactin levels may be caused by pituitary adenomas (benign tumors), thyroid disorders, kidney problems, certain medications (like antipsychotics or birth control), or stress. Low prolactin levels can result from pituitary damage, pregnancy, or certain medical conditions affecting hormone production.
How Often Should This Test Be Done?
If you have a known condition affecting prolactin (like a pituitary tumor), your provider may recommend regular monitoring. Otherwise, this test is typically done only when symptoms or concerns suggest it’s needed, such as infertility, irregular periods, or unexplained breast milk production.
Can Diet or Lifestyle Affect Prolactin Levels?
Some studies suggest stress, caffeine, smoking, and certain medications (like SSRIs or opioids) may influence prolactin levels. However, diet alone rarely affects results unless linked to underlying health conditions (e.g., thyroid issues). Always follow your provider’s advice regarding lifestyle factors before testing.
  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