NHS Factsheet

NHS website

Potassium test

Find out why and when a potassium test may be needed.

18 October 2022

Introduction

A potassium test measures the amount of potassium in blood serum, the fluid part of your blood.

Potassium ↗ is a mineral that helps:

  • nerves and muscles "communicate"
  • nutrients move into cells and waste products move out of cells
  • the heart function healthily

There are several reasons why a doctor might recommend you have a potassium test, including:

If you have low potassium levels, you may have a heart problem, such as an irregular heartbeat ↗.

If you have high potassium levels, your heart muscle activity may be reduced.

Both situations are serious and can be life threatening.

In rare cases, potassium levels may be low through a poor diet.

Good sources of dietary potassium include:

  • fruit, particularly bananas
  • some vegetables
  • pulses
  • nuts and seeds
  • milk
  • fish
  • shellfish
  • beef
  • chicken
  • turkey
  • bread

Read more about the potassium test on Lab Tests Online UK ↗