: Oxalate 12-Hour Urine Rate
: This test measures the amount of oxalate excreted in a 12-hour urine collection, reported as a rate. It helps evaluate the cause of recurrent calcium kidney stones.
[": The 12-hour urine oxalate rate helps your care team understand how much oxalate your body removes in urine."]
Key facts at a glance
- LOINC
- 57375-8
- Short code
- Oxalate 12h Ur-mRate
- Synonyms
- Oxalate 12h Ur-mRate
- Category
- chemistry
- 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 This Test Measures
: Oxalate is a natural substance found in many foods and made in small amounts by your body. When oxalate is high in urine, it can bind with calcium and contribute to calcium oxalate kidney stones. This test measures how much oxalate is passed in urine over 12 hours, expressed as a rate.
: How the Specimen Is Collected
: You collect all urine for a 12-hour period in a container provided by your lab. Your care team usually asks you to collect after you urinate and discard the first sample, then save all urine for the next 12 hours, including the final sample exactly at the end. Follow the lab's timing and storage instructions carefully.
: What the Rate Reflects
: Reporting a rate over time, rather than a single spot measurement, helps account for how concentrated or diluted your urine is. The oxalate rate gives your clinician a picture of long-term oxalate output, which can be influenced by diet, gut health, and genetic factors.
: Preparation and Factors That Affect Results
: Your care team may ask you to keep your usual diet or to follow specific diet instructions before the test, because food can affect oxalate levels. Ask if any medications, vitamins, or supplements (such as high-dose vitamin C) should be adjusted. Hydration and completeness of collection can affect results.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
: The 12-hour urine oxalate rate is used in the evaluation of calcium oxalate kidney stones, especially when stones recur. It can help assess dietary and intestinal sources of oxalate as well as genetic conditions that raise oxalate handled by the kidneys. Results must be interpreted by your clinician in the context of your symptoms, other urine and blood tests, and your overall history. No numeric reference range is given here because ranges vary by laboratory.
Short name
: Oxalate, 12-hr urine
Frequently asked questions
: Why does the test require a 12-hour urine collection?
: Can what I eat change the result?
: What happens if my oxalate level is high?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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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