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Test Code UK24HR Potassium, Urine, 24 Hour, LAB436


Indirect Potentiometric

Performing Laboratory

St. Luke's Hospital Cedar Rapids

Specimen Requirements


Preferred: 24-hour urine collection

Specimen Volume: 0.5 mL from a 24-hour timed urine collection. No preservative.

                    Refrigerate specimen during collection, and send specimen refrigerated.

Stability: 24 hour urine collection for potassium should be made without addition of

                 preservatives. Store at 2-8ºC or frozen for delayed analysis.

Collection Instructions: Obtain 24-hour urine jug from laboratory

Note: 1. Starting and ending times of collection are required.

           2. When a 24-hour urine for potassium is done, a PV (period and volume) must

               also be ordered and resulted. (FOR LAB USE ONLY).



Reference Values

25-125 mmol/24 hours

Day(s) Test Set Up

Monday through Sunday

Test Classification and CPT Coding

81050-Timed urine measurement


Useful For

Renal function is the major mechanism by which potassium is regulated.

Urine K+ levels are useful when evaluating patients with hypokalemia.  A urine K+ concentration of more than 10 mmol/L indicates the kidney is responsible for the loss of potassium.  A urine K+ concentration less than 10 mmol/L strongly suggests that the gastrointestinal tract is the route of potassium loss.