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Lysine/Creatinine Ratio, Urine

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

This urine test measures lysine relative to creatinine, helping account for variations in urine concentration and assess how much lysine is being excreted.

Quick summary

["The result helps evaluate lysine excretion and metabolism, but it must be interpreted alongside diet, symptoms, and other tests."]

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

Key facts at a glance

LOINC
30048-3
Short code
Lysine/Creat Ur-Rto
Synonyms
Lysine/Creat Ur-Rto
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 lysine in urine compared with the amount of creatinine. Creatinine is used as a reference marker because its amount in urine tends to reflect urine concentration. The ratio can help assess how much filtered lysine is being passed into the urine.

Why might I need this test?

A urine lysine-to-creatinine ratio may be used to evaluate lysine metabolism or kidney handling of amino acids. It may be ordered for a child or adult with a suspected amino-acid disorder, nutritional concern, or condition that affects how the body processes and releases lysine.

How is the test performed?

A urine sample is collected and tested in a laboratory to measure lysine and creatinine. The laboratory then calculates the ratio. The result may be based on a spot sample or a timed collection, depending on the instructions from your healthcare professional.

How do I prepare for the test?

Follow the collection instructions provided with the test order, including whether a first-morning, spot, or timed urine sample is required. Tell the healthcare team about major changes in your diet, supplements, medicines, pregnancy, or recent illness, since these may affect interpretation.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Urine Lysine/Creatinine Ratio

Frequently asked questions

What does a urine lysine-to-creatinine ratio measure?
It compares the amount of lysine with the amount of creatinine in urine. Using creatinine helps account for how concentrated or dilute the urine sample is.
What might cause an elevated result?
Possible causes include increased lysine intake, reduced kidney reabsorption, or an inherited or acquired problem affecting lysine metabolism. The result must be interpreted with the rest of the clinical evaluation.
Do I need to change my diet before this test?
Do not make major dietary changes unless your healthcare professional specifically instructs you to do so. Because lysine intake can affect the result, maintaining your usual diet may provide the most representative measurement; follow the instructions on your test order.
  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