Cystine in Urine (Quantitative, 24-Hour Collection)
This test measures the amount of cystine, a rare amino acid, in your urine over a 24-hour period. It helps diagnose conditions like cystinuria, where the body fails to properly absorb cystine.
["Cystinuria is a genetic disorder that can lead to kidney stones if untreated."]
Key facts at a glance
- LOINC
- 25155-3
- Short code
- Cystine Cry #/area UrnS HPF
- Synonyms
- Cystine Cry #/area UrnS HPF
- Category
- chemistry
- Sample
- urine
- Container
- Sterile urine container
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- microscopy-light-hpf
- 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
Why This Test Is Done
Your doctor may recommend this test if you have symptoms like frequent kidney stones, pain in your back or side, nausea, or unexplained weight loss. It’s also used to monitor people with a known history of cystinuria or kidney stones caused by cystine.
What to Expect Before the Test
You’ll need to collect all urine for a full 24-hour period. Start by emptying your bladder completely at the beginning of the collection period (e.g., 8:00 AM). Store all urine in a clean container, adding fresh urine every time you urinate. Bring the entire collection to your doctor’s office or lab.
What Happens During the Test
No special preparation is needed beyond the urine collection. The lab will analyze the sample for cystine levels using a specialized method, such as high-performance liquid chromatography (HPLC).
What the Results Mean
High levels of cystine in urine strongly suggest cystinuria. Your doctor will compare your results to known reference ranges for this condition and discuss potential next steps, such as dietary changes or medications.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Elevated cystine levels confirm cystinuria, a genetic disorder that can cause recurrent kidney stones. Early diagnosis allows for treatment to reduce stone formation, improve kidney function, and prevent complications like chronic kidney disease.
Frequently asked questions
What causes cystine to build up in urine?
How is cystinuria diagnosed besides this test?
Can diet help manage cystine levels?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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