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Prolactin (Serum) 2-Hour Post-Eating

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

This test measures your prolactin hormone level after eating to help check for conditions affecting hormone balance, such as pituitary disorders or thyroid issues.

Quick summary

["A post-meal prolactin test helps doctors assess how your body responds to food-related hormonal changes."]

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

Key facts at a glance

LOINC
1613-9
Short code
Prolactin 2h p L-D PO SerPl-mCnc
Synonyms
Prolactin 2h p L-D PO 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 This Test Is Done

Your doctor may order this test if they suspect a hormonal imbalance, such as hyperprolactinemia (too much prolactin), pituitary tumors, or thyroid disorders. It can also help evaluate symptoms like infertility, irregular periods, or unexplained headaches.

What to Expect Before the Test

You’ll fast for 8–12 hours before the test, then eat a standard meal to trigger hormonal changes. Blood is drawn after 2 hours. Avoid caffeine or alcohol before testing.

How the Test Works

A blood sample is taken to measure prolactin, a hormone that regulates breast milk production and reproductive functions. The test checks levels after eating to detect abnormal responses.

What the Results Mean

Results may indicate whether your prolactin levels spike normally after eating or if they’re consistently elevated, which could signal underlying health concerns.

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 (Post-Meal)

Frequently asked questions

How long does fasting last before the test?
You’ll need to fast for 8–12 hours before eating the meal that triggers the test. Your doctor will provide exact instructions.
What should I avoid before the test?
Avoid caffeine, alcohol, and heavy meals 24 hours before testing. Smoking may also affect results, so ask your doctor if you should quit.
Is this test painful?
The blood draw is quick and may cause mild discomfort, but it’s similar to other routine blood tests. You can take pain relievers if needed.
  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