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Methylmalonate/Creatinine Ratio, Urine

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

This urine test measures methylmalonate relative to creatinine, helping account for differences in urine concentration.

Quick summary

["An elevated result may reflect abnormal methylmalonate metabolism or impaired vitamin B12 processing."]

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

Key facts at a glance

LOINC
56664-6
Short code
Methylmalonate/Creat Ur-Rto
Synonyms
Methylmalonate/Creat Ur-Rto
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 the amount of methylmalonate in urine compared with the amount of creatinine. Creatinine is used as a reference to help reduce the effect of variations in urine concentration.

Why might I need this test?

The test may be used to evaluate suspected methylmalonic acidemia, a group of inherited metabolic disorders, or to assess vitamin B12-related metabolism. It may also be ordered when evaluating unexplained developmental, neurologic, or metabolic symptoms.

How is the test performed?

A urine sample is collected and analyzed in the laboratory to determine the methylmalonate-to-creatinine ratio. The exact laboratory method does not need to be specified by the test name.

How do I prepare for the test?

Follow the collection instructions provided by your healthcare professional or laboratory, including whether a first-morning or other timed urine sample is required. Tell the laboratory if you take vitamin B12 supplements, because supplementation can affect the result.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

An elevated methylmalonate/creatinine ratio may occur with methylmalonyl-CoA mutase deficiency or other disorders affecting methylmalonate metabolism. Increased levels can also be associated with vitamin B12 deficiency or reduced kidney function, so results must be interpreted alongside symptoms, medications, supplements, and other tests.

Short name

Urine methylmalonate/creatinine ratio

Frequently asked questions

What does the methylmalonate/creatinine ratio measure?
It compares the amount of methylmalonate with the amount of creatinine in urine. This helps account for how concentrated or dilute the urine sample is.
What can cause an elevated result?
Possible causes include inherited methylmalonate metabolism disorders, vitamin B12 deficiency, and reduced kidney function. Your healthcare professional will interpret the result in your clinical context.
Does taking vitamin B12 affect this test?
Yes. Vitamin B12 supplementation can lower methylmalonate levels, so the laboratory and your clinician should be told about any supplements or injections you receive.
  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