Nephrology

Potassium Deficit

Estimates total body potassium deficit in hypokalemia.

Parameters

mEq/L
mEq/L

Potassium Deficit Result

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FormulaPotassium Deficit (mEq) ≈ [(Target K⁺ - Measured K⁺) / 0.3] × 100

Clinical Pearls

Helps quantify the amount of potassium chloride (KCl) needed to replete a hypokalemic patient.

Limitations

This is a rough estimate. The actual deficit can be much larger in severe, chronic hypokalemia. Serum pH also affects potassium (acidosis shifts K out of cells, alkalosis shifts K into cells), which this formula does not adjust for. Magnesium deficiency makes potassium refractory to correction.