How does acidosis affect serum potassium?

For every 0.1 decrease in pH, serum K+ rises approximately 0.6 mEq/L (range 0.4-1.2). H+ enters cells in exchange for K+ exiting. This is most pronounced in mineral (non-anion gap) acidosis.

How does alkalosis affect serum potassium?

Alkalosis causes K+ to shift intracellularly: for every 0.1 rise in pH, serum K+ falls approximately 0.6 mEq/L. Hypokalaemia and alkalosis often coexist in vomiting, diuretic use.

Why is this important clinically?

In diabetic ketoacidosis, serum K+ may appear normal or high despite severe total body depletion due to acidosis-driven shift. Insulin and fluid therapy correct acidosis, precipitating rapid hypokalaemia.

Potassium-pH Shift Calculator

Estimate the effect of pH on serum potassium. Serum K+ changes approximately 0.6 mEq/L per 0.1 unit change in pH (inverse relationship).

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