Kynurenine/Creatinine Ratio, Urine
This urine test measures kynurenine relative to creatinine, helping account for differences in urine concentration.
["The ratio shows how much kynurenine is present in urine relative to creatinine."]
Key facts at a glance
- LOINC
- 53107-9
- Short code
- KYN/Creat Ur-sRto
- Synonyms
- KYN/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?
Kynurenine is a substance produced when the body breaks down the amino acid tryptophan. This test measures kynurenine and creatinine in urine and calculates their ratio. Creatinine is used as a reference because its amount in urine varies with urine concentration.
Why might I need this test?
A urine kynurenine/creatinine ratio may be used to evaluate tryptophan metabolism. Your clinician may order it when investigating nutritional, digestive, neurologic, or other health conditions, sometimes alongside other laboratory tests.
How is the test performed?
A urine specimen is collected according to the laboratory's instructions. The laboratory measures the amounts of kynurenine and creatinine and calculates the ratio. The result is interpreted together with your symptoms, medical history, and other tests.
How do I prepare for the test?
Follow any urine-collection instructions provided by your clinician or laboratory. If a timed collection is requested, record the start and end times and collect all urine for the specified period. Drinking and urination patterns can affect urine concentration, so consistency with the instructions is important.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
A higher or lower kynurenine/creatinine ratio may reflect changes in tryptophan metabolism or urine concentration. Elevated results have been associated with nutritional deficiencies, certain intestinal or inflammatory conditions, and some other illnesses, but the finding is not specific to one condition. Results should be interpreted by a clinician in the context of the individual patient.
Short name
Urine kynurenine/creatinine ratio
Frequently asked questions
What does the kynurenine/creatinine ratio show?
Is this the same as a serum kynurenine test?
Can I interpret an abnormal result on my own?
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