Corrected Calcium

Albumin-adjusted serum calcium

Measured total calcium

Serum albumin

Enter measured calcium and albumin to calculate

Evidence

Original publication

Payne RB, Little AJ, Williams RB, Milner JR. Interpretation of serum calcium in patients with abnormal serum proteins. Source of the widely used "+0.8 mg/dL per 1 g/dL albumin below 4.0" adjustment.

British Medical Journal, 1973

Open source

Guideline

The albumin correction is approximate and performs poorly in critical illness, chronic kidney disease, and marked acid–base disturbance. Measure ionised calcium when an accurate value is needed.

Last reviewed: 2026-09

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MedScore is an educational and clinical decision-support tool. It does not provide a diagnosis, a treatment, or a drug-dosing recommendation, and it does not replace clinical judgement or local guidelines. Confirm every result against the original source before acting on it. The treating clinician remains responsible for all decisions.