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Urine Uracil-to-Creatinine Ratio

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

Measures the relative amount of uracil compared with creatinine in urine. Creatinine is used to account for differences in urine concentration.

Quick summary

["This urine test can help identify increased uracil excretion, which may be associated with reduced DPD enzyme activity or certain medications."]

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

Key facts at a glance

LOINC
13819-8
Short code
Uracil/Creat Ur
Synonyms
Uracil/Creat 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 uracil relative to creatinine in a urine sample. The ratio helps show whether an unusual amount of uracil is being excreted while adjusting for how concentrated the urine is.

Why might I need this test?

The test may be used to evaluate reduced dihydropyrimidine dehydrogenase (DPD) activity, a condition that can affect how the body processes fluoropyrimidine medicines. It may also be used to monitor or assess the risk of certain medication side effects.

How is the test performed?

A urine specimen is collected according to the laboratory’s instructions. The laboratory measures uracil and creatinine and calculates the uracil-to-creatinine ratio.

How do I prepare for the test?

Follow the instructions provided for urine collection, including whether a random or timed specimen is needed. Tell your clinician about fluoropyrimidine medicines, such as 5-fluorouracil or capecitabine, and do not stop prescribed treatment without medical advice.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

An elevated ratio may indicate increased uracil excretion, potentially associated with reduced DPD activity. This can be relevant in people taking fluoropyrimidine medicines because low DPD activity may increase the risk of severe treatment-related toxicity. Results must be interpreted with age, medications, symptoms, and other laboratory findings.

Short name

Uracil/Creatinine Ratio, Urine

Frequently asked questions

What does the uracil-to-creatinine ratio measure?
It shows the amount of uracil in urine relative to creatinine. This helps reduce the effect of variations in urine concentration.
Why is creatinine included in the test?
Creatinine is a waste product used as a marker of urine concentration. Including it allows the laboratory to compare uracil levels more accurately between samples.
Does an abnormal result mean I have cancer?
No. An abnormal result does not by itself diagnose cancer. It may reflect medication exposure, reduced DPD activity, or other factors that require clinical interpretation.
  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