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Methylmalonate-to-Creatinine Ratio, Urine

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

A urine test that measures methylmalonate relative to creatinine, helping evaluate possible methylmalonic acidemia or vitamin B12 deficiency.

Quick summary

["An elevated urine methylmalonate-to-creatinine ratio can occur with methylmalonic acidemia, vitamin B12 deficiency, or impaired kidney function."]

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

Key facts at a glance

LOINC
25116-5
Short code
Methylmalonate/Creat Ur-sRto
Synonyms
Methylmalonate/Creat Ur-sRto
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 relative to the amount of creatinine. Creatinine is used as a reference because its level in urine can vary with urine concentration and kidney function.

Why might I need this test?

It may be used to help evaluate suspected methylmalonic acidemia, a group of inherited conditions that can cause metabolic problems. It may also be used in the assessment of vitamin B12 deficiency, especially when blood test results need further evaluation.

How is the test performed?

A urine sample is collected and analyzed in the laboratory. The laboratory measures methylmalonate and creatinine and calculates the methylmalonate-to-creatinine ratio.

How do I prepare for the test?

Follow the urine-collection instructions provided by your healthcare professional or laboratory. Your clinician may advise whether to collect a first-morning or timed urine sample and may request dietary or supplement changes, particularly if you take vitamin B12.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Urine methylmalonate-to-creatinine ratio

Frequently asked questions

What does the urine methylmalonate-to-creatinine ratio measure?
It compares the amount of methylmalonate in urine with the amount of creatinine. This helps account for differences in urine concentration.
What conditions can cause an elevated result?
Possible causes include methylmalonic acidemia and vitamin B12 deficiency. Impaired kidney function can also raise the ratio, so other test results are important.
Do I need to collect a 24-hour urine sample?
Not always. The laboratory may request a spot urine, often including a first-morning sample, or a timed collection. Confirm the specific collection instructions 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