Is my Potassium normal?
Free blood test checker · Standard + longevity-optimal ranges
What is a normal Potassium level?
Potassium is the most abundant intracellular electrolyte. It's essential for heart rhythm, muscle contraction, and nerve function. Both high and low potassium can cause dangerous heart arrhythmias. Normal range is 3.5-5.0 mEq/L. Even small deviations can be clinically significant.
| Range | Values |
|---|---|
| Standard Reference | 3.5–5 mEq/L |
| High Risk | > 5.5 mEq/L |
| Low Risk | < 3 mEq/L |
What causes abnormal Potassium levels?
Low potassium (hypokalemia) is commonly caused by diuretics, prolonged vomiting or diarrhea, excessive sweating, poor dietary intake, and certain kidney conditions. High potassium (hyperkalemia) is caused by kidney disease (most common), ACE inhibitors, potassium-sparing diuretics, tissue damage, and excess supplementation. Note: hemolyzed blood samples can falsely elevate potassium.
When should you see a doctor?
See your doctor if potassium is below 3.5 or above 5.0 mEq/L. Symptoms of low potassium include muscle cramps, weakness, and irregular heartbeat. Symptoms of high potassium include palpitations, chest pain, and muscle weakness. Severely abnormal potassium (below 2.5 or above 6.5) is a medical emergency.
Potassium and longevity
Potassium is critical for cardiac electrical conduction — abnormal levels are one of the few lab values that can cause immediate, life-threatening arrhythmias. In the longevity context, adequate potassium intake (3,400 mg/day for men, 2,600 mg for women) is associated with lower blood pressure, reduced stroke risk, and improved kidney function. Most Americans consume only half the recommended amount. The sodium-to-potassium ratio may matter more than either mineral alone — a lower ratio is consistently associated with better cardiovascular outcomes. Note: hemolyzed blood samples (cells broken during the draw) are the most common cause of falsely elevated potassium — always confirm unexpected results.
Where to get a Potassium test
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Related biomarkers
These biomarkers are often tested alongside Potassium for a more complete picture.
Frequently asked questions
What is a normal potassium level?
What causes low potassium?
What foods are high in potassium?
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Sources: Reference ranges based on AHA/ACC, ADA, and AACE clinical guidelines. Biological variation data from Ricos/Westgard database. Longevity-optimal ranges reflect targets used by preventive and functional medicine practitioners.
Last reviewed: April 2026. This tool provides general health information and is not a substitute for professional medical advice, diagnosis, or treatment. Always consult your healthcare provider about your specific results.