Uric Acid, 24 Hour, Urine
Use
The test is useful for the assessment and management of patients with kidney stones, particularly uric acid stones. Uric acid is the end-product of purine metabolism, freely filtered by the glomeruli, and mostly reabsorbed by the tubules with active tubular secretion occurring as well. Urinary uric acid excretion is elevated in a significant proportion of these patients and can be affected by dietary purines, pharmacological agents, and nucleoprotein-rich foods.
Special Instructions
X-ray dyes and contrast media will affect test results. If a kidney X-ray with dye or e.g., computerized tomography (CT) scan with contrast has been performed, patients should wait a minimum of 1 day before starting collection. In cases of bile duct X-ray, they should wait 7 days. Complete the Renal Diagnostics Test Request form if not ordering electronically.
Limitations
High levels of bilirubin and ascorbic acid may interfere with the measurement of uric acid levels. Reference values have not been established for patients under 18 years of age. Conditions such as polycythemia and leukemia or intake of nucleoprotein-rich foods can elevate urine uric acid levels.
FDA ApprovedNew York Approved
Methodology
Automated Analyzer (Clinical Chemistry)
Biomarkers
LOINC Codes
- 3087-4
- 3087-4
- 13362-9
- 3167-4
- 21587-1
Result Turnaround Time
1-3 days
Related Documents
For more information, please review the documents below
Specimen
Urine
Volume
5 mL
Minimum Volume
1 mL
Container
Plastic, 5 mL tube or a clean, plastic aliquot container with no metal cap or glued insert
Collection Instructions
Collect urine for 24 hours. Refrigerate specimen within 4 hours of completion of the collection.
Patient Preparation
Urine must be collected before tablets for gallbladder X-ray. Follow instructions regarding X-ray dye usage and potential wait times.
Causes for Rejection
High levels of interfering substances like bilirubin and ascorbic acid.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 7 days |
| Refrigerated | 14 days |
| Frozen | 30 days |