Potassium, 24 Hour, Urine
Use
The test is used for determining the cause of hyper- or hypokalemia by measuring the potassium level in urine collected over a 24-hour period. Potassium is the major intracellular cation, and its regulation is crucial for maintaining neuromuscular excitability, heart function, and fluid balance. The kidneys play an essential role in regulating potassium excretion, which can be influenced by various conditions affecting tubular function or aldosterone levels. This test can provide valuable insights into renal and non-renal losses of potassium, particularly in cases of hypokalemia.
Special Instructions
The test requires a 24-hour urine collection. Ensure that the specimen is refrigerated within 4 hours of completing the collection. Proper collection and preservation are critical for accurate results.
Limitations
Ion-selective electrodes used in the test are selective but not specific, as other monovalent cations can interfere with the measurement outside the physiologic range. It is important to ensure that specimen collection and handling are done correctly to avoid diagnostic confusion.
FDA ApprovedNew York Approved
Methodology
Other (Potentiometric, Indirect Ion-Selective Electrode (ISE))
Biomarkers
LOINC Codes
- 2829-0
- 2829-0
- 13362-9
- 3167-4
Result Turnaround Time
1-2 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 24-Hour collection.
Storage Instructions
Refrigerated (preferred) for 14 days, Ambient for 7 days, Frozen for 30 days
Causes for Rejection
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 7 days |
| Refrigerated | 14 days |
| Frozen | 30 days |