Cystine Quantitative, Urine

Casandra

Casandra Test Code AR12927Version 1 (DRAFT)

Performing Lab

Lab ARUP LaboratoriesLab Test ID 0081106CPT Code 82131

Cystine Quantitative, Urine

Also known as: QNT CYS U

Clinical Use

Order Test

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.

Test Details

New York Approved

Methodology

Mass Spectrometry

Biomarkers

Cystine

Analyte

Cystine, Urine - Quantitative • Concentration / Level • Quantitative (Continuous) (e.g., copies/mL, % expression)

Cystine, 24 Hour Urine • Concentration / Level • Quantitative (Continuous) (e.g., copies/mL, % expression)

Cystine, Urine - per volume • Concentration / Level • Quantitative (Continuous) (e.g., copies/mL, % expression)

LOINC Codes

Result Codes

56677-8
2179-0
32169-5
35674-1
81323-8
19153-6

Result Turnaround Time

3-7 days

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.