Macroprolactin (Serum)
This test measures a form of prolactin—a hormone that regulates breast milk production and other reproductive functions—that may appear in higher amounts when bound to a large protein carrier, called a macroprotein.
["Macroprolactin can affect hormone balance and may require evaluation if prolactin levels seem unusually high."]
Key facts at a glance
- LOINC
- 72680-2
- Short code
- Macroprolactin SerPl Ql
- Synonyms
- Macroprolactin SerPl Ql
- 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 macroprolactin test if you have symptoms like breast changes, irregular menstrual periods, or signs of hormonal imbalance. It’s also used to confirm or investigate suspected macroprolactinemia, a condition where macroprolactin is abnormally elevated, which can mimic symptoms of true prolactin excess.
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 your blood is drawn in the morning. Wear comfortable clothing and plan to stay near the testing site for a short time, as blood draws typically take a few minutes.
What Happens During the Test?
A healthcare professional will insert a small needle into a vein in your arm or hand to draw blood. You may feel a slight pinch, but it usually doesn’t cause discomfort. The blood sample is then sent to a lab for analysis.
What Do the Results Mean?
Results are interpreted by your provider based on your symptoms and medical history. Elevated macroprolactin levels may indicate macroprolactinemia, which can cause hormonal imbalances. Further testing or evaluation may be needed to determine the cause and next steps.
Reference range
Adult males: 2-18 ng/mL; Females: 2-29 ng/mLN/A
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.
Macroprolactin can be misleadingly high in some cases because it binds to proteins differently than regular prolactin. If your prolactin levels are elevated but other tests suggest normal hormone function, a macroprolactin test helps distinguish between true prolactin excess and macroprolactinemia. This distinction is important for guiding treatment and avoiding unnecessary interventions.
Short name
Macroprolactin Test
Frequently asked questions
What causes macroprolactin to be elevated?
How is macroprolactin different from regular prolactin?
Can macroprolactin levels change over time?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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