Why correct calcium for albumin?

Approximately 40-45% of serum calcium is protein-bound, primarily to albumin. Hypoalbuminaemia spuriously lowers total calcium without affecting ionised (active) calcium.

How is corrected calcium calculated?

Corrected calcium (mg/dL) = Measured total calcium + 0.8 x (4.0 minus serum albumin g/dL). For SI units: Corrected Ca (mmol/L) = Measured Ca + 0.02 x (40 minus albumin g/L).

When should ionised calcium be measured directly?

Ionised calcium measurement is preferred in critically ill patients, during cardiac surgery, in acid-base disorders, and when albumin correction may be unreliable (e.g., multiple myeloma).

Corrected Calcium for Albumin Calculator

Calculate corrected serum calcium when albumin is abnormal. Formula: Corrected Ca (mg/dL) = Measured Ca + 0.8 x (4 minus albumin).

Use the full interactive calculator below, or

Related Calculators

Cinacalcet Dosing

Medical

Phosphate Binders