Metabolic
Potassium
LOINC 2823-3 · mEq/L
Ranges
Reference range: 3.5–5 mEq/L
What it is
Potassium is an electrolyte essential for nerve signals, muscle function and a steady heartbeat.
Why it matters
Because both high and low levels can affect heart rhythm, potassium is one of the most important electrolytes to keep in range.
What high values can mean
A higher value can relate to kidney issues, certain medications or sample handling, and can affect the heart.
What low values can mean
A lower value can follow fluid loss, some diuretics or poor intake and may cause weakness or cramps.
How to improve it
Care targets the cause; potassium-rich foods help a low level, while a high level may need intake adjusted under guidance.
Food & lifestyle
Bananas, potatoes, beans, leafy greens and many fruits and vegetables are rich in potassium.
Preparing for the test
Often part of a metabolic panel; fasting is not specifically required — follow your lab.
When to talk to a doctor
Discuss an abnormal potassium with a doctor promptly, as it can affect the heart.
Related markers
Sources
- MedlinePlus (NIH)
- Testing.com (AACC)
Content reviewed on June 26, 2026
Medical disclaimer
This content is for educational purposes only. It is not medical advice and does not diagnose, treat, or prevent any condition. Reference ranges vary between laboratories — always use the range printed on your report and discuss your results with a healthcare professional.
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