Sodium, 24-Hour Urine
Use
Work up volume depletion, acute renal failure, acute oliguria, and differential diagnosis of hyponatremia.1 Division of hyponatremia into hypervolemia or not, edema or not, and urinary Na+ less than or greater than 10 mmol/L provides a classification of hyponatremia.2 History of diuretics, other drug intake, setting of osmotic diuresis or not, serum or plasma electrolytes and other factors are needed.
Special Instructions
The test request form must include the date and time collection started, date and time collection finished, and total 24-hour urine volume. Ensure the lid is securely screwed on and the container is labeled with the patient's full name and the collection start and end details.
Limitations
This test may face limitations in its applicability for diagnosis when spot urine sodium levels are considered without additional data. Low sodium excretion may appear in early obstructive uropathy, acute glomerulonephritis, and x-ray contrast acute renal failures, while high sodium excretion in oliguria suggests acute tubular necrosis.
Methodology
Automated Analyzer (Clinical Chemistry)
Biomarkers
LOINC Codes
- 2956-1
- 2955-3
- 2956-1
Result Turnaround Time
1 day
Related Documents
For more information, please review the documents below
Specimen
Urine
Volume
10 mL aliquot
Minimum Volume
1 mL aliquot
Container
Plastic urine container without preservative
Collection Instructions
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). Screw the lid on securely. Container must be labeled with patient's full name, date and time collection started, and date and time collection finished.
Storage Instructions
Room temperature
Causes for Rejection
Improper labeling
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 14 days |
| Refrigerated | 14 days |
| Frozen | 14 days |