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Oxalate and Creatinine, 24-Hour Urine

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

Measures the amount of oxalate in urine collected over 24 hours, with creatinine used to help evaluate the result.

Quick summary

["This test helps identify unusually high urinary oxalate, which can contribute to calcium oxalate kidney stones."]

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

Key facts at a glance

LOINC
13788-5
Short code
Oxalate/Creat 24h Ur
Synonyms
Oxalate/Creat 24h 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 oxalate, a normal breakdown product, in urine collected for 24 hours. Creatinine, a waste product filtered by the kidneys, is measured to help assess how much oxalate is being excreted.

Why might I need this test?

Your clinician may order this test if you have kidney stones, recurring calcium oxalate stones, or another condition associated with increased oxalate levels. It can also help evaluate unexplained high urinary oxalate.

How is the test performed?

You collect all urine produced for 24 hours into a labeled container provided by the laboratory. The urine volume and collection time are recorded so the laboratory can calculate the daily amount of oxalate and creatinine.

How do I prepare for the test?

Follow your clinician's and laboratory's collection instructions exactly. Do not change your diet or take vitamin C supplements unless your clinician specifically advises it, because these can affect oxalate results.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

An elevated result may indicate hyperoxaluria, which can increase the risk of calcium oxalate kidney stones. High urinary oxalate can be associated with dietary oxalate, intestinal malabsorption, certain medications, or inherited disorders. Your clinician will interpret the result with your symptoms, medical history, other urine tests, and imaging when relevant.

Short name

24-Hour Urine Oxalate

Frequently asked questions

What does a high urine oxalate result mean?
It means more oxalate than expected is being excreted in the urine. This may increase the risk of calcium oxalate stones and can be related to diet, intestinal disease, medications, or an inherited condition.
Why is creatinine included in this test?
Creatinine helps clinicians evaluate urine concentration and interpret the oxalate measurement. In a 24-hour collection, both results reflect the total amount excreted during the collection period.
How do I correctly collect 24-hour urine?
Begin at the time specified by the laboratory and collect every urine sample for the next 24 hours, including the final sample at the end of the period. Keep the container refrigerated if instructed, record the total volume, and return it promptly.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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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