Cystine Quantitative, Urine
Also known as: QNT CYS U
Use
This test is used for monitoring treatment of patients previously diagnosed with cystinuria. It helps to evaluate the effectiveness of the treatment regimen by quantifying cystine levels in urine. This is essential for patients with cystinuria, a metabolic disorder that leads to the formation of cystine stones in the kidneys.
Special Instructions
Ensure that the Biochemical Genetic Testing Patient History Form is submitted with the order to provide clinical context necessary for interpretation. Avoid dilution of the urine specimen during collection. Properly document total volume and collection time interval on both the transport tube and test request form.
Limitations
This test is intended specifically for monitoring patients known to have cystinuria and is not designed for diagnosing or ruling out cystinuria. For such purposes, refer to an Amino Acids Quantitative by LC-MS/MS, Urine test (2009419). Specimens kept at room temperature or refrigerated are unacceptable due to potential degradation of the analyte, impacting the accuracy of results.
New York Approved
Methodology
Mass Spectrometry
Biomarkers
LOINC Codes
- 56677-8
- 2179-0
- 32169-5
- 35674-1
- 81323-8
- 19153-6
Result Turnaround Time
3-7 days
Related Documents
For more information, please review the documents below
Specimen
Urine
Volume
4 mL
Minimum Volume
3 mL
Container
ARUP Standard Transport Tubes
Collection Instructions
Collect 24-hour or other timed urine collection. Mix urine well before transferring to transport tube. Record total volume and collection interval on transport tube and test request form.
Patient Preparation
Avoid collection of dilute urine by ensuring proper hydration balance. Document age, gender, diet (including TPN therapy), drug therapy, and family history as they are critical for result interpretation.
Storage Instructions
Freeze specimens immediately after collection to maintain stability. Avoid storage at ambient temperature or refrigeration.
Causes for Rejection
Refrigerated or room temperature specimens.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | Unacceptable |
| Refrigerated | Unacceptable |
| Frozen | 1 month |