Corrected Calcium Calculator
Calculate corrected calcium for low albumin levels.
Enter total serum calcium and albumin to get the adjusted calcium value.
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Corrected Calcium
Corrected calcium adjusts for low albumin levels, since about 40% of serum calcium is bound to albumin. Low albumin causes falsely low total calcium readings.
Formula (Payne equation):
Corrected Ca (mg/dL) = Total Ca (mg/dL) + 0.8 x (4.0 - Albumin (g/dL))
SI units:
Corrected Ca (mmol/L) = Total Ca (mmol/L) + 0.02 x (40 - Albumin (g/L))
Normal ranges:
- Total calcium: 8.5–10.5 mg/dL (2.12–2.62 mmol/L)
- Albumin: 3.5–5.0 g/dL (35–50 g/L)
- Corrected calcium normal: 8.5–10.5 mg/dL
Interpretation:
- < 8.5 mg/dL: Hypocalcemia (low calcium)
- 8.5–10.5 mg/dL: Normal
- > 10.5 mg/dL: Hypercalcemia (high calcium)
- > 12.0 mg/dL: Severe hypercalcemia (urgent)
When to use this correction:
- Albumin < 4.0 g/dL (most hospitalized patients)
- Liver disease, nephrotic syndrome, malnutrition
- Not needed if ionized calcium is measured directly
Important: This calculator is for educational purposes only. Always consult a healthcare provider for medical interpretation.