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Cystine and Creatinine, Urine and Stool

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

Measures cystine and creatinine in urine and may assess cystine in stool to help evaluate cystinuria and monitor treatment.

Quick summary

["This test helps identify excessive cystine loss in urine, a condition that can cause kidney stones."]

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

Key facts at a glance

LOINC
50054-6
Short code
Hemicystine/Creat Ur-sRto
Synonyms
Hemicystine/Creat 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 cystine, an amino acid, in urine and stool. Urinary creatinine is also measured to help interpret the amount of cystine being excreted, and stool testing can help assess intestinal cystine handling.

Why might I need this test?

It may be used to investigate cystinuria, an inherited condition in which the kidneys release too much cystine into the urine. Cystine can form crystals and kidney stones, so testing may also be used to monitor treatment and reduce the risk of stone formation.

How is the test performed?

A urine sample is collected and analyzed for cystine and creatinine. A stool sample may also be collected and tested for cystine. Your laboratory will provide specific containers and collection instructions.

How do I prepare for the test?

Follow the laboratory's instructions for urine and stool collection, including any timed collection period. You may need to collect all urine and stool for the specified period and record the start and end times. Fasting is generally not required unless your clinician directs otherwise.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Cystinuria profile

Frequently asked questions

What does an abnormal cystine result mean?
High urinary cystine can suggest cystinuria or another problem with cystine metabolism. The result should be reviewed with urinary creatinine, kidney stone history, genetic testing when appropriate, and other clinical findings.
Can this test determine whether I have cystinuria?
It can support the diagnosis by showing increased urinary cystine excretion. Confirmation may also involve genetic testing or evaluation by a specialist, especially when family history or stone symptoms are present.
Why is creatinine measured with urine cystine?
Creatinine helps show how concentrated the urine is, allowing the amount of cystine to be interpreted more accurately. This is especially helpful with spot urine samples.
  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