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Urine Lysine-to-Creatinine Ratio

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

A urine test that compares the amount of lysine with the amount of creatinine, helping evaluate how much lysine is being lost in the urine.

Quick summary

["An elevated ratio may indicate increased urinary lysine loss, but diet, age, kidney function, and urine concentration can also affect the result."]

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

Key facts at a glance

LOINC
13769-5
Short code
Lysine/Creat Ur
Synonyms
Lysine/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 the ratio of lysine to creatinine in urine. Lysine is an essential amino acid, while creatinine is a waste product produced by muscle and filtered by the kidneys. Comparing the two helps account for variations in urine concentration.

Why might I need this test?

A urine lysine-to-creatinine ratio may be used to evaluate abnormal amino acid loss in the urine or to assess nutrition in children. It may also be ordered as part of an evaluation of inherited kidney conditions that affect amino acid handling.

How is the test performed?

A urine sample is collected and tested in the laboratory. The laboratory measures the concentrations of lysine and creatinine and calculates the ratio of one to the other.

How do I prepare for the test?

Follow your clinician's instructions about the type and timing of urine collection. Fasting is usually not required, but your clinician may ask you to record or avoid certain foods, medicines, or supplements because they can affect amino acid levels.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Urine Lysine/Creatinine Ratio

Frequently asked questions

Does this test require a 24-hour urine collection?
Not always. It may be performed on a spot urine sample or a timed collection, depending on the laboratory and the reason for testing. Confirm the collection instructions with your clinician.
Can diet affect the result?
Yes. Recent protein intake and lysine-rich foods can influence urinary lysine levels, so your clinician may ask you to follow specific dietary instructions before collection.
Why is the result reported as a ratio?
Urine concentration can vary widely between samples. Using creatinine as a comparison helps reduce the effect of urine dilution or concentration on the 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