Test Details
Methodology
Liquid chromatography/tandem mass spectrometry (LC/MS-MS)
Result Turnaround Time
4 - 6 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Use
This test measures levels of cystine in urine to detect presence of cystinuria and nephrolithiasis.
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This test 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.
This test was developed and its performance characteristics determined by Labcorp. It has not been cleared or approved by the Food and Drug Administration.
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 This test was developed and its performance characteristics determined by Labcorp. It has not been cleared or approved by the Food and Drug Administration. |
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. This test was developed and its performance characteristics determined by Labcorp. It has not been cleared or approved by the Food and Drug Administration. |
Specimen Requirements
Specimen
Urine (24-hour)
Volume
5 mL aliquot
Minimum Volume
2.5 mL aliquot (Note: This volume does not allow for repeat testing.)
Container
Plastic urine container without preservative (preferred) or 6N HCl. Note that the addition of 6N HCl may adversely impact other tests for kidney stones or urinalysis.
Plastic urine container without preservative (preferred) |
Plastic urine container without preservative (preferred) or 6N HCl. Note that the addition of 6N HCl may adversely impact other tests for kidney stones or urinalysis. |
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.
Reference Range
2.1−58.0 mg/24 hours
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
LOINC® Map
| Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
|---|---|---|---|---|---|---|
| 700195 | Cystine, Quant. 24 hr Urine | 700381 | Cystine, Quantitative, Urine | mg/L | 32169-5 | |
| 700195 | Cystine, Quant. 24 hr Urine | 700382 | Cystine, Quant, Ur | mg/24 hr | 2179-0 | |
| Order Code | 700195 | |||||
| Order Code Name | Cystine, Quant. 24 hr Urine | |||||
| Order Loinc | ||||||
| Result Code | 700381 | |||||
| Result Code Name | Cystine, Quantitative, Urine | |||||
| UofM | mg/L | |||||
| Result LOINC | 32169-5 | |||||
| Order Code | 700195 | |||||
| Order Code Name | Cystine, Quant. 24 hr Urine | |||||
| Order Loinc | ||||||
| Result Code | 700382 | |||||
| Result Code Name | Cystine, Quant, Ur | |||||
| UofM | mg/24 hr | |||||
| Result LOINC | 2179-0 |