Uracil/Creatinine Ratio, Urine
This urine test measures uracil relative to creatinine. It can help evaluate uracil metabolism and may be used when monitoring fluoropyrimidine treatment.
["The ratio can help identify abnormal uracil metabolism, including possible dihydropyrimidine dehydrogenase deficiency or fluoropyrimidine-related toxicity."]
Key facts at a glance
- LOINC
- 25140-5
- Short code
- Uracil/Creat Ur-sRto
- Synonyms
- Uracil/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 uracil in urine relative to the amount of creatinine. Creatinine is used as a marker of urine concentration, helping account for differences in how dilute or concentrated the urine sample is.
Why might I need this test?
The test may be used to evaluate how your body breaks down uracil and pyrimidines. It may also be ordered during treatment with fluoropyrimidine medicines, such as fluorouracil or capecitabine, to help assess the risk of treatment-related toxicity.
How is the test performed?
A urine sample is collected and analyzed in the laboratory. The laboratory measures uracil and creatinine and calculates their ratio; no blood draw is required.
How do I prepare for the test?
Follow the collection instructions provided by the laboratory, including whether a single urine sample or timed collection is required. Tell your clinician about all medicines and supplements you are taking, especially fluoropyrimidine medicines.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
An elevated urine uracil/creatinine ratio may reflect increased uracil production, reduced breakdown of uracil, or effects of fluoropyrimidine therapy. Reduced activity of the enzyme dihydropyrimidine dehydrogenase is one possible cause, particularly in people experiencing significant medication toxicity. Results must be interpreted with kidney function, medication exposure, symptoms, and other laboratory findings by the treating clinician.
Short name
Urine Uracil/Creatinine Ratio
Frequently asked questions
Is this the same as a urine uracil test?
Why is this test checked during cancer treatment?
Do I need to fast for this 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