Metanephrine Free/Creatinine Ratio, Urine
This urine test measures free metanephrine relative to creatinine. It helps evaluate whether the body may be producing excess catecholamines.
["An elevated ratio may suggest an adrenal or other catecholamine-producing tumor, but results must be interpreted with symptoms and other tests."]
Key facts at a glance
- LOINC
- 44337-4
- Short code
- Metaneph Free/Creat Ur
- Synonyms
- Metaneph Free/Creat Ur
- Category
- kidney
- Sample
- urine
- Container
- Sterile urine container
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Specimen volume
- 10 mL
- Stability
- Room temperature: 2h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 4–24 hours
- Order
- routine
What is this test?
This test measures metanephrine, a breakdown product of catecholamines such as epinephrine and norepinephrine, in urine. Dividing by urine creatinine helps account for differences in urine concentration.
Why might I need this test?
It may be ordered to evaluate episodes of headache, sweating, rapid heartbeat, or high blood pressure. The test is used to help look for pheochromocytoma, paraganglioma, or another source of excess catecholamines.
How is the test performed?
A urine sample is tested for free metanephrine and creatinine, and the laboratory calculates their ratio. The result is interpreted along with the collection method, symptoms, medications, and other laboratory findings.
How do I prepare for the test?
Follow the collection instructions provided by your healthcare professional or laboratory. If a 24-hour collection is requested, collect all urine for the specified period; for a single urine sample, provide the sample when instructed. Some labs ask that caffeine, alcohol, nicotine, and strenuous exercise be avoided around collection.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
An elevated metanephrine-to-creatinine ratio may occur with catecholamine-producing tumors such as pheochromocytoma or paraganglioma. High levels can also result from physical stress, acute illness, certain foods, caffeine, nicotine, or medications, so an abnormal result usually requires clinical review and sometimes repeat or confirmatory testing.
Short name
Urine free metanephrine/creatinine ratio
Frequently asked questions
What does the urine metanephrine/creatinine ratio measure?
Does an elevated result mean I have a tumor?
Should I stop medications before taking this test?
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