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Test ID RKUR Potassium, Random, Urine

Useful For

Determining the cause for hyper- or hypokalemia using a random urine specimen

Method Name

Potentiometric, Indirect Ion-Selective Electrode (ISE)

Reporting Name

Potassium, Random, U

Specimen Type


Specimen Required

Supplies: Aliquot tube, 5 mL (T465)

Container/Tube: Plastic, 5-mL tube

Specimen Volume: 4 mL

Collection Instructions:

1. Collect a random urine specimen.

2. No preservative.

Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Urine Refrigerated (preferred) 14 days
  Frozen  30 days
  Ambient  7 days

Reference Values

No established reference values

Random urine potassium may be interpreted in conjunction with serum potassium, using both values to calculate fractional excretion of potassium.


The calculation for fractional excretion (FE) of potassium (K) is

FE(K)= ([K(urine) X Creat(serum)]/[K(serum) X Creat(urine)]) X 100

Day(s) Performed

Monday through Sunday

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information


LOINC Code Information

Test ID Test Order Name Order LOINC Value
RKUR Potassium, Random, U 2828-2


Result ID Test Result Name Result LOINC Value
RKUR Potassium, Random, U 2828-2

Test Classification

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

NY State Approved


Report Available

Same day/1 to 2 days