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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MédicoDoctorMedical 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.

Apenas para uso educacional. Esta ferramenta não substitui o julgamento clínico ou protocolos locais.

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

Como funciona

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).

Fórmula de cálculo

Ca_corr = Ca_meas + 0.8 × (4.0 - Albumin)

Exemplos de cálculo

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

Por que usar essa ferramenta no seu dia a dia?

Evite tratamentos desnecessários. Este serviço evita a administração perigosa e dispendiosa de cálcio intravenoso a pacientes que realmente não precisam dele, mantendo o gerenciamento de eletrólitos seguro e baseado em evidências.