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Oxalate/Creatinine Ratio, Urine

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

A urine test that measures oxalate relative to creatinine, helping evaluate urinary oxalate levels when evaluating kidney stones.

Quick summary

["This test helps assess how much oxalate is being excreted in the urine, which may be relevant to the risk of calcium oxalate kidney stones."]

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

Key facts at a glance

LOINC
13483-3
Short code
Oxalate/Creat Ur
Synonyms
Oxalate/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?

The urinary oxalate/creatinine ratio measures the amount of oxalate in urine relative to the amount of creatinine. Creatinine is used to account for variations in urine concentration, making results easier to compare across samples.

Why might I need this test?

This test may be used when evaluating recurrent kidney stones, especially calcium oxalate stones, or when monitoring people with conditions or treatments that can increase urinary oxalate. It is commonly part of a broader metabolic stone workup.

How is the test performed?

A urine sample is analyzed to determine its oxalate and creatinine concentrations, and the results are used to calculate the ratio. Your clinician may request a single urine sample or a collection over 24 hours, depending on the purpose of the test.

How do I prepare for the test?

Follow the collection instructions provided by your clinician or laboratory. If a 24-hour collection is requested, collect all urine for the specified period and record the start and end times. Tell the laboratory if you recently took vitamin C or any supplements containing oxalate, because these can affect the result.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Urinary Oxalate/Creatinine Ratio

Frequently asked questions

Does this test diagnose kidney stones?
No. It helps evaluate urinary oxalate as part of a broader assessment, but it is not a test for the presence or location of a stone.
Why is creatinine included in the test?
Creatinine helps adjust the oxalate measurement for how concentrated the urine is. This makes the result more useful when urine concentration varies.
Can diet or supplements affect the result?
Yes. High dietary oxalate and vitamin C supplements can increase urinary oxalate. Tell your clinician about relevant dietary changes and supplements before interpreting the result.
  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