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).

⚕ Clinical Disclaimer: These calculators are for educational and reference purposes only. Always verify results with qualified clinical judgment and current clinical guidelines. Do not use as a sole basis for medical decisions.

How to Use

Enter the values for the scenario you are assessing. Calculate corrected serum calcium when albumin is abnormal. Formula: Corrected Ca (mg/dL) = Measured Ca + 0.8 x (4 minus albumin). Use the corrected calcium result to inform your calculation.

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