Kidney & Electrolytes

Potassium Blood Test -- Monitor This Essential Electrolyte

Potassium works alongside sodium, chloride, calcium, and magnesium to conduct electrical impulses throughout the body. It is critical for maintaining a steady heartbeat and enabling normal muscle and digestive function. The body regulates potassium levels tightly, so even small deviations can signal underlying issues with diet, medication, or organ function.

Why Test Potassium?

Testing potassium is important for uncovering lifestyle-related health risks early. A diet low in fruits, vegetables, and legumes -- or high in sodium and processed foods -- can upset potassium balance. Monitoring is also essential if you take medications such as NSAIDs, ACE inhibitors, diuretics, or beta-blockers, which can affect potassium levels.

What Do High Potassium Levels Mean?

High potassium (hyperkalaemia) can result from kidney disease, diabetes, dehydration, infection, or medications such as NSAIDs, ACE inhibitors, beta-blockers, and potassium supplements. A high-potassium diet rich in fruits and vegetables can also contribute. Severe hyperkalaemia may cause dangerous heart rhythm disturbances.

What Do Low Potassium Levels Mean?

Low potassium (hypokalaemia) is commonly caused by vomiting, diarrhoea, excessive sweating, or use of corticosteroids and certain diuretics. Adrenal gland disorders can also reduce potassium. Symptoms can range from muscle weakness to cardiac arrhythmias.

Symptoms to Watch For

  • Muscle weakness or cramps
  • Fatigue
  • Heart palpitations or irregular heartbeat
  • Numbness or tingling
  • Nausea or constipation

Who Should Get Tested?

  • People with high blood pressure or heart disease
  • Those taking diuretics, ACE inhibitors, or NSAIDs
  • Anyone with kidney disease or diabetes
  • Individuals experiencing muscle cramps or fatigue
  • Athletes concerned about electrolyte balance

How to Prepare for Your Test

No preparation is needed. Do not clench and relax your fist during the blood draw, as this can falsely elevate the result. Bring valid ID to your appointment.

Order Your Blood Test

Test your Potassium levels with an accredited Swedish laboratory. Results within days, reviewed by Wellth.

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Frequently Asked Questions

Can clenching my fist during the test affect the result?
Yes. Repeatedly clenching and relaxing the fist can release potassium from muscle cells and give a falsely high reading. Stay relaxed during the draw.
What foods are high in potassium?
Bananas, avocados, sweet potatoes, spinach, beans, and citrus fruits are all rich sources. Most people benefit from adequate potassium intake, but those with kidney disease may need to limit it.
Why is potassium important for the heart?
Potassium helps generate the electrical impulses that keep the heart beating in a regular rhythm. Both too much and too little potassium can cause dangerous arrhythmias.
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Reviewed by

Wellth Team

Wellth

Our content is written and reviewed by Wellth, and fact-checked against peer-reviewed research and current Swedish clinical guidelines.

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Medical Disclaimer

The information on this page is provided for informational purposes only and does not constitute professional medical advice, diagnosis, or treatment. Wellth provides health information and testing services but is not a substitute for clinical care. Always consult a qualified healthcare provider if you have questions about a medical condition. If you are experiencing severe or urgent symptoms, contact your doctor or call 1177 Vårdguiden. Blood test results should be interpreted by a qualified healthcare professional in the context of your complete medical history.