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Corrected Calcium Calculator

Estimate albumin-corrected calcium. Use local lab reference ranges and consider ionized calcium when clinically indicated.

Inputs

Units

Measured calcium mg/dL

Albumin g/dL

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Enter calcium and albumin to calculate corrected calcium.

Disclaimer: For educational purposes only. Not a substitute for clinical judgment.

Conventional (US units): Corrected Ca (mg/dL) = Measured Ca + 0.8 × (4.0 − albumin [g/dL])
SI approximation: Corrected Ca (mmol/L) = Measured Ca + 0.02 × (40 − albumin [g/L])

Albumin correction is imperfect (especially in critical illness). Consider measuring ionized calcium when accuracy matters.
Interpret calcium in context of symptoms, ECG changes, and concurrent Mg/PO₄ abnormalities.

Payne RB, et al. Interpretation of serum calcium in patients with abnormal serum proteins. BMJ. 1973.