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Tyrosine/Creatinine Ratio, 24-Hour Urine

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

This test measures the amount of tyrosine relative to creatinine in urine collected over 24 hours. It can help evaluate abnormal tyrosine metabolism.

Quick summary

["An elevated urine tyrosine/creatinine ratio may suggest increased tyrosine or reduced creatinine and requires clinical interpretation."]

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

Key facts at a glance

LOINC
44415-8
Short code
Tyrosine/Creat 24h Ur
Synonyms
Tyrosine/Creat 24h 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 the amount of the amino acid tyrosine relative to creatinine in a 24-hour urine sample. Creatinine is used as a comparison to help account for urine concentration and the amount collected.

Why might I need this test?

A clinician may order this test when there is concern about elevated tyrosine, especially in a child with symptoms of a metabolic disorder. It may also be used during follow-up of a person with an abnormal tyrosine level or a condition that affects protein metabolism.

How is the test performed?

You collect all urine for 24 hours according to the laboratory's instructions. The laboratory then measures tyrosine and creatinine and calculates their ratio.

How do I prepare for the test?

Follow the laboratory's 24-hour collection instructions, including when to start and how to store the container. Keep the container refrigerated if instructed, record any missed collections, and tell the laboratory about medications, supplements, illness, and unusual changes in protein intake.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

24-Hour Urine Tyrosine/Creatinine Ratio

Frequently asked questions

Does this test measure tyrosine in blood?
No. This test measures tyrosine in urine collected over 24 hours and compares it with urine creatinine. Your clinician may order blood tests as part of the same evaluation.
What if part of the urine collection is missed?
Tell the laboratory and clinician because a missed collection can make the result unreliable. The collection may need to be repeated, depending on how much was missed and the laboratory's instructions.
Can diet or medicines affect the result?
Yes. Protein intake, supplements, certain medicines, and acute or chronic illness may affect urinary tyrosine or creatinine. Share relevant dietary and medication information with your clinician when discussing the result.
  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