Preferred Sample Type

Urine Electrolytes

Suitable Specimen Types

Plain Spot Urine 24 Hour Urine Plain

Urine Electrolytes

Specimen Volume

0.1 mL urine

Sample Preparation


Turnaround Time

< 1 day

Sample Processing In Laboratory


Sample Stability

4 ºC

General Information

This test measures both urinary sodium, urinary potassium and urinary urea.

Urinary sodium, together with assessment of volume status, is useful in the differential diagnosis of hyponatramia. Urinary sodium levels are also frequently ordered during the workup of acute renal failure with the fractional excretion of sodium used as an important marker in distinguishing pre-renal from post-renal failure.

Urinary potassium may be ordered in the workup of hypokalemia. In case of GI loss of potassium, the urine potassium will be low. In case of renal loss of potassium, the urine potassium levels will be high. Decreased levels of urine potassium are also seen in hypoaldosteronism and adrenal insufficiency.



Urea and electrolytes (sodium and potassium)  can be measured on a 24h collection or a random sample

Reference Range

None Given. The results must be interpreted together with serum electrolytes and clinical details.


  • EQA Status: NEQAS
  • EQAS Scheme: Yes

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