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Urine Xanthine-to-Creatinine Ratio

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

A urine test that measures xanthine relative to creatinine, helping assess urinary xanthine excretion while accounting for urine concentration.

Quick summary

["This ratio can help evaluate increased xanthine excretion, including possible xanthinuria and xanthine kidney stone risk."]

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

Key facts at a glance

LOINC
38371-1
Short code
Xanthine/Creat Ur-sRto
Synonyms
Xanthine/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 xanthine in urine compared with the amount of creatinine. Creatinine is used as a reference to help account for how concentrated or dilute the urine sample is.

Why might I need this test?

Your clinician may order this test if you have kidney stones, a family history of xanthine stones, or symptoms suggesting an inherited problem of purine metabolism. It may also be used to monitor treatment for xanthinuria.

How is the test performed?

A urine sample is collected and analyzed for xanthine and creatinine. The laboratory then calculates the xanthine-to-creatinine ratio from the measured values.

How do I prepare for the test?

Follow the laboratory's urine collection instructions, including whether a single sample or a timed collection is required. Tell your clinician about your diet, fluid intake, supplements, and medicines such as allopurinol, because these can affect the result.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Urine xanthine/creatinine ratio

Frequently asked questions

What does the xanthine-to-creatinine ratio measure?
It compares urinary xanthine with urinary creatinine. This helps show how much xanthine is being excreted while reducing the effect of differences in urine concentration.
Why is a urine ratio used instead of a xanthine result alone?
Urine xanthine levels naturally vary with how concentrated the urine is. Using creatinine as a reference makes results from different samples easier to compare.
Can diet or medicines affect this test?
Yes. Purine-rich foods, hydration, and medicines that alter purine metabolism, including allopurinol, may affect the result. Ask your clinician whether any dietary or medication changes are needed before testing.
  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