What Is Potassium in a Blood Test?
Potassium regulates heartbeat, nerve signals, and muscle contraction. Even small deviations can be dangerous.
Normal Range
- 3.5–5.1 mEq/L
- Hyperkalemia: above 5.5 mEq/L — potentially life-threatening
- Hypokalemia: below 3.5 mEq/L
- Severe hyperkalemia: above 6.5 mEq/L — medical emergency
High Potassium Causes
- Kidney disease
- Medications — ACE inhibitors, ARBs, potassium-sparing diuretics
- Adrenal insufficiency
- Tissue breakdown
- Lab artifact — hemolyzed sample (most common cause of mild elevation)
Low Potassium Causes
- Diuretics
- Vomiting or diarrhea
- Hyperaldosteronism
- Magnesium deficiency
Why It Matters
- Heart is extremely sensitive to potassium
- High = arrhythmia, cardiac arrest risk
- Low = weakness, cramps, arrhythmia
- Part of BMP and CMP panels
Source: NLM MedlinePlus, American Association for Clinical Chemistry.
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