Sodium vs potassium — why both?

Full answer

Sodium and potassium are both essential electrolytes but serve different roles. Sodium is the dominant extracellular cation, driving fluid balance, blood pressure, and neurologic function — sodium abnormalities most often reflect water-balance problems (dehydration, SIADH, diuretics). Potassium is the dominant intracellular cation, critical for cardiac conduction, neuromuscular function, and acid-base balance — potassium abnormalities are acutely dangerous and most often reflect kidney function, medications (ACEi/ARB, diuretics), or acid-base shifts. Both are reviewed within the CMP and interpreted with hydration, medications, and kidney function context.

Educational. Not a substitute for individualized provider review.