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:
- to help diagnose or monitor kidney disease, which is the most common cause of high potassium levels
- if you have heart-related problems, such as high blood pressure (hypertension)
- if you take certain medicines that can affect your potassium levels
- if you have diabetes and your doctor thinks you may have diabetic ketoacidosis, a serious complication caused by a lack of insulin in the body
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
- nuts and seeds
Page last reviewed: 18 October 2022
Next review due: 18 October 2025