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Cystine/Creatinine Ratio, Urine

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

Measures the amount of cystine relative to creatinine in urine to help evaluate urinary cystine excretion, particularly when cystinuria is suspected.

Quick summary

["This urine test helps assess how much cystine is being lost in the urine, which is important when evaluating cystinuria and kidney stone risk."]

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

Key facts at a glance

LOINC
32616-5
Short code
Hycs-Cys diS/Creat Ur-Rto
Synonyms
Hycs-Cys diS/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 cystine and creatinine in a urine sample and calculates their ratio. Cystine is an amino acid, while creatinine is a waste product that can help account for urine concentration.

Why might I need this test?

It may be ordered when there is a family history of cystinuria, recurrent kidney stones of certain types, or concern that the kidneys are losing excessive amounts of cystine. The result is usually considered with urine cystine levels and other clinical findings.

How is the test performed?

A urine specimen is collected and tested in the laboratory for cystine and creatinine. The laboratory then compares the two measurements to calculate the cystine-to-creatinine ratio.

How do I prepare for the test?

Follow the collection instructions provided by your healthcare professional. A clean-catch urine sample is commonly requested, and your clinician will tell you whether a timed or 24-hour collection is required.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

An elevated ratio may indicate increased urinary cystine excretion, which can occur with cystinuria and may increase the risk of cystine kidney stones. Results should be interpreted by a clinician because urine concentration, kidney function, age, diet, and hydration can affect the ratio.

Short name

Urine cystine/creatinine ratio

Frequently asked questions

What does the cystine/creatinine ratio measure?
It compares the amount of cystine in urine with the amount of creatinine in the same sample. This helps express urinary cystine relative to urine concentration.
Why is this test important for people with recurrent kidney stones?
Cystine stones can form when the kidneys release too much cystine into the urine. Measuring the ratio can help identify unusually high cystine excretion.
Does an abnormal result confirm cystinuria?
No. An abnormal result may support further evaluation, but cystinuria is generally confirmed using additional urine or genetic testing and the person's medical history.
  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