Why do we correct calcium for albumin?

About half of serum calcium is bound to albumin. If albumin levels are low, the total measured calcium will be low even if the active (ionized) calcium is normal.

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MedicoDoctorMedical Laboratory Scientist

Corrected Calcium Calculator

Calculate serum calcium levels corrected for albumin, providing a more accurate reflection of physiologically active calcium.

Calcium is essential for bone health, nerve signaling, and muscle function. However, standard lab tests measure 'total' calcium, which includes calcium bound to proteins like albumin. If albumin is low, the total calcium result can be misleading. This calculator 'corrects' the calcium level to show what it would be if the patient had normal albumin levels.

Solo uso didattico. Questo strumento non sostituisce il giudizio clinico o i protocolli locali.

Measured calcium

Albumin (g/L)

Calcium units

Albumin input stays g/L; conversion handled automatically.

Corrected calcium

2.2mmol/L

Corrected Calcium is 2.2 mmol/L

Ca + 0.02 * (40 - Alb) = 2.1 + 0.02 * (40 - 35)

Measured calcium2.1 mmol/L

Albumin (g/L)35 g/L

Unitsmmol/L

Come funziona

The tool uses the standard Payne formula, which adds a correction factor for every unit that the patient's albumin is below the normal reference (usually 4.0 g/dL or 40 g/L).

Formula di calcolo

Ca_corr = Ca_meas + 0.8 × (4.0 - Albumin)

Esempi di calcolo

1. **Low Protein**: Ca 8.0, Albumin 2.0 = **9.6 (Normal)**.

Perché utilizzare questo strumento nella tua vita quotidiana?

Evitare trattamenti non necessari. Questo servizio impedisce la somministrazione pericolosa e costosa di calcio per via endovenosa a pazienti che non ne hanno effettivamente bisogno, mantenendo la gestione degli elettroliti sicura e basata sull'evidenza.