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Thymine/Creatinine, Urine — Substance Ratio

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

This urine test compares the amount of thymine with creatinine, helping account for how concentrated or dilute the urine sample is.

Quick summary

["The result shows how much thymine is being excreted relative to creatinine in the urine."]

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

Key facts at a glance

LOINC
48157-2
Short code
Thymine/Creat Ur-sRto
Synonyms
Thymine/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 thymine, a building block of DNA, in urine and compares it with the amount of creatinine. Creatinine is a muscle-breakdown product commonly used to account for differences in urine concentration.

Why might I need this test?

A urine thymine/creatinine ratio may help a clinician evaluate thymine metabolism and the amount of thymine being excreted. It may be used when an inherited disorder of pyrimidine or thymine metabolism is suspected or when monitoring is appropriate.

How is the test performed?

A urine specimen is collected and analyzed in a laboratory. The laboratory measures thymine and creatinine, then calculates their ratio to reduce the effect of variations in urine concentration.

How do I prepare for the test?

Follow your clinician's urine-collection instructions, including any specified collection time or amount. Do not change medications, supplements, or diet unless your healthcare professional tells you to, as these can affect the result.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

An elevated ratio may indicate increased urinary thymine excretion or altered thymine metabolism, including certain inherited pyrimidine-metabolism disorders. A lower ratio may reflect reduced excretion or other factors affecting urine concentration. The result must be interpreted with symptoms, medical history, medications, and other laboratory tests.

Short name

Urine thymine/creatinine ratio

Frequently asked questions

What does the thymine/creatinine ratio measure?
It measures the amount of thymine in urine relative to the amount of creatinine. This helps normalize the thymine result when urine is more or less concentrated.
Is this the same as a routine urine creatinine test?
No. A routine urine creatinine test measures creatinine by itself, while this test uses creatinine to calculate a ratio with thymine.
What can cause an abnormal result?
Abnormal results may occur with inherited disorders of thymine or pyrimidine metabolism, medication use, dietary supplement exposure, or differences in urine concentration. Your clinician can interpret the result in your specific situation.
  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