Corrected Calcium Calculator
Calcium adjusted for albumin (total-calcium correction)
Equation & limitations
- Equation
- Corrected Ca = measured Ca + 0.8 × (4 − albumin)
- Version
- Common total-calcium correction (reference albumin 4.0 g/dL)
- Source
- Defined by Pharmapedia for this tool; the widely used 0.8 × (4 − albumin) correction.
- Appropriate in
- Adults with hypoalbuminaemia where ionised calcium is unavailable.
- Limitations
- An approximation; the correction factor varies between references (0.8–1.0) and is unreliable in critical illness.
- Ionised calcium is the better measure in acute illness — corrected total calcium can still mislead.
- mg/dL units only; entering mmol/L will give a wrong result.
For educational use. Results support, and do not replace, clinical judgement — check them against the patient and local guidelines.