Corrected Calcium

Calcium value adjusted for albumin level — more accurate in cancer patients.

What it is

Corrected calcium adjusts the measured total calcium for low albumin levels. Formula: corrected Ca = measured Ca + 0.02 × (40 – albumin in g/L). Since albumin binds calcium, hypoalbuminaemia causes falsely low total calcium readings.

Why it matters

Cancer patients often have low albumin. Using uncorrected calcium in this context underestimates true physiological calcium levels. Corrected calcium gives a more accurate picture of clinically relevant calcium status — preventing both underdiagnosis of hypercalcaemia and unnecessary supplementation.

How to test

Calculated from total calcium and albumin values. Reported automatically on many panels.

This information is for educational purposes only. Always discuss testing and interpretation of results with your care team.

Optimal range

2.2–2.6 mmol/L (same reference range as total calcium).

How often

Each oncology panel where albumin is also measured.