Tyrosine/Creatinine Ratio, 24-Hour Urine
Measures the amount of tyrosine relative to creatinine in urine collected over 24 hours to help evaluate tyrosine metabolism.
["This test helps identify unusually high urinary tyrosine levels, which may be related to diet, supplementation, or an inherited metabolic condition."]
Key facts at a glance
- LOINC
- 25996-0
- Short code
- Tyrosine/Creat 24h Ur-sRto
- Synonyms
- Tyrosine/Creat 24h 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 tyrosine relative to creatinine in a 24-hour urine collection. Creatinine is used as a reference marker for the amount of urine produced, helping account for variations in urine concentration.
Why might I need this test?
It may be ordered to evaluate an elevated tyrosine level or investigate an inborn error of metabolism, particularly in a child with developmental concerns, seizures, unusual symptoms, or a family history of a metabolic disorder. It may also be used to monitor dietary treatment or tyrosine supplementation.
How is the test performed?
You collect all urine for exactly 24 hours, usually in a labeled container provided by the laboratory or healthcare provider. The total volume and collection times are recorded, and a portion of the urine is analyzed to calculate the tyrosine-to-creatinine ratio.
How do I prepare for the test?
Follow the collection instructions provided by your clinician and record when you begin and end the collection. The urine should generally be kept refrigerated during collection and returned promptly. Do not change your diet, supplements, or medications unless your clinician advises you to do so.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
An elevated ratio may indicate excessive tyrosine production or reduced breakdown, as can occur with hereditary disorders of tyrosine metabolism. Results may also be affected by a high-protein diet, tyrosine supplementation, illness, or kidney function, so the result must be interpreted with the rest of your medical evaluation.
Short name
24-Hour Urine Tyrosine/Creatinine Ratio
Frequently asked questions
Does this test require a timed urine collection?
Can I take tyrosine supplements before the test?
What if I miss part of the 24-hour collection?
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