Biomarker · Electrolytes

Potassium

Potassium is an electrolyte essential for heart and muscle function. What a potassium blood test shows and common causes of high or low levels.

Written by LON6EVITY Editorial Team · Last updated

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Why potassium matters

Potassium helps nerves and muscles work, including the heart. Both high and low levels can affect heart rhythm.

Causes of abnormal levels

MedlinePlus lists kidney disease and some blood pressure medicines as causes of high potassium, and vomiting, diarrhoea and some diuretics as causes of low potassium.

Testing issues

Potassium can be falsely high if blood cells break during or after the blood draw. Unexpected results are often repeated.

Reference ranges

Reference ranges differ between laboratories, units and methods, and depend on age, sex and your overall clinical picture. A single result is not a diagnosis — interpret it with a qualified clinician.

Factors that can affect the result

  • Kidney function
  • Blood pressure medicines
  • Diuretics
  • Vomiting and diarrhoea
  • Sample handling

Questions people commonly ask

Why was my potassium test repeated?
A falsely high result can occur from the sample itself, so repeating it is common.

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Sources

  1. Potassium Blood Test. MedlinePlus, U.S. National Library of Medicine.
  2. Electrolyte Panel. MedlinePlus, U.S. National Library of Medicine.