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Urine Oxalate-to-Creatinine Ratio

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

Measures urine oxalate relative to creatinine to help evaluate oxalate excretion and the risk of calcium oxalate kidney stones.

Quick summary

["An elevated ratio may indicate increased oxalate excretion, which can raise the risk of calcium oxalate kidney stones."]

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

Key facts at a glance

LOINC
34350-9
Short code
Oxalate/Creat Ur-sRto
Synonyms
Oxalate/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 oxalate in urine relative to the amount of creatinine. Creatinine is used to account for how concentrated the urine sample is.

Why might I need this test?

Your clinician may order this test if you have kidney stones, recurrent calcium oxalate stones, or a condition that may increase oxalate levels. It can also help monitor treatment for excessive oxalate excretion.

How is the test performed?

A urine sample is tested to determine the oxalate-to-creatinine ratio. The collection may be a single urine sample or part of a timed collection, depending on the instructions provided by your laboratory.

How do I prepare for the test?

Follow your clinician's urine collection instructions exactly and note the collection date and time. Do not change your diet or stop medications unless your clinician tells you to, and ask the laboratory how to store the sample if it will not be delivered promptly.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

A higher-than-expected ratio may indicate that you are excreting too much oxalate in your urine. This can contribute to calcium oxalate kidney stones and may occur with dietary oxalate, intestinal absorption problems, or certain rare metabolic disorders. The result should be interpreted with symptoms, medical history, and other kidney or stone tests.

Short name

Urine Oxalate/Creatinine Ratio

Frequently asked questions

What does an elevated urine oxalate-to-creatinine ratio mean?
It usually means that more oxalate is being excreted in the urine than expected for the amount of creatinine. Your clinician will consider possible dietary, intestinal, medication-related, or inherited causes.
Does this test diagnose a kidney stone?
No. Imaging and other clinical information are generally needed to confirm a kidney stone. This test can help evaluate the metabolic conditions that may contribute to calcium oxalate stones.
Why is creatinine included in the test?
Urine concentration can vary from sample to sample. Creatinine provides a reference amount so the urine oxalate result can be interpreted more consistently.
  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