Oxalate/Creatinine Ratio, Urine — Mass/Mass
Measures urine oxalate relative to urine creatinine to help evaluate oxalate excretion and the risk of calcium oxalate kidney stones.
["An elevated ratio may indicate increased oxalate excretion, which can raise the risk of calcium oxalate kidney stones."]
Key facts at a glance
- LOINC
- 108504-2
- Short code
- Oxalate/Creat Msmt Ur
- Synonyms
- Oxalate/Creat Msmt 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 the amount of oxalate in urine compared with the amount of creatinine in the same urine sample. Creatinine is used as a marker of urine concentration, allowing the oxalate result to be interpreted even when urine is more or less concentrated.
Why might I need this test?
A clinician may order this test when evaluating recurring calcium oxalate kidney stones, unexplained excess urinary oxalate, or suspected intestinal malabsorption. It may also be used to monitor people with conditions or treatments that increase stone risk.
How is the test performed?
A urine sample is collected and analyzed in the laboratory to determine its oxalate and creatinine content. The laboratory then calculates the oxalate-to-creatinine ratio.
How do I prepare for the test?
Follow the laboratory's collection instructions, including whether a first-morning or timed urine sample is required. Your clinician may advise you to avoid unusually high-oxalate foods or oxalate-containing supplements before collection, but do not change your diet or medications without guidance.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
A higher-than-expected oxalate-to-creatinine ratio can indicate hyperoxaluria, which may increase the risk of calcium oxalate kidney stones. Possible contributors include dietary oxalate, vitamin C supplements, reduced intestinal absorption, inflammatory bowel disease, or certain rare inherited disorders. Interpretation depends on the collection method, age, kidney function, diet, and other clinical findings.
Short name
Urinary Oxalate-to-Creatinine Ratio
Frequently asked questions
Does this test diagnose kidney stones?
Why is creatinine included in the result?
Should I stop taking supplements before the 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