Cystine, Quantitative, Urine
Use
Measures levels of cystine in urine to detect presence of cystinuria and nephrolithiasis.
Special Instructions
The test request form must state date and time collection started and finished. The test request form must state whether patient is taking penicillamine or tiopronin or captopril. Measure and record the total 24-hour urine volume on the test request form.
Limitations
Penicillamine and Tiopronin combine with cystine and lower cystine level in urine. Captopril and other thiol-containing medications/substances may also interfere with this test. 6N HCl may be added as a preservative but may adversely impact other tests for kidney stones or urinalysis.
Methodology
Mass Spectrometry
Biomarkers
LOINC Codes
- 2179-0
- 32169-5
- 32169-5
- 2179-0
Result Turnaround Time
4-6 days
Related Documents
For more information, please review the documents below
Specimen
Urine
Volume
5 mL aliquot
Minimum Volume
2.5 mL aliquot
Container
Plastic urine container without preservative (preferred) or 6N HCl
Collection Instructions
24-hour urine: Instruct the patient to void at 8 AM and discard the specimen. Then collect all urine, including the final specimen voided at the end of the 24-hour collection period (ie, 8 AM the next morning). The urine container may be kept at room temperature or refrigerated during collection. Measure and record total urine volume. Mix well, aliquot, and freeze the aliquot for storage and shipping. Label container with patient's name, date of birth, date and time collection started, and date and time collection completed.
Storage Instructions
After aliquoting, specimens should immediately be frozen and maintained frozen during shipping as well as at the testing facility until tested.
Causes for Rejection
Receipt of non-frozen sample
Other tests from different labs that may be relevant