Corrected Calcium Calculator

How to calculate Corrected Calcium calculator?

Corrected calcium adjusts total serum calcium for low albumin to better estimate the physiologically active calcium concentration.

Use the formula: Corrected calcium (mg/dL) = total_calcium + 0.8 × (4.0 − albumin)

Using the Corrected Calcium calculator calculator: an example

Example values: total serum calcium = 8.2 mg/dL and albumin = 2.5 g/dL.

Step-by-step calculation:

1. Start with measured total calcium: 8.2 mg/dL.
2. Calculate albumin difference: 4.0 − 2.5 = 1.5 g/dL.
3. Apply the factor: 0.8 × 1.5 = 1.2 mg/dL.
4. Add to total calcium: 8.2 + 1.2 = 9.4 mg/dL (corrected calcium).

Frequently Asked Questions

Why is albumin used to correct calcium?

Most circulating calcium is bound to albumin; correcting accounts for albumin changes that alter total calcium without reflecting ionized calcium.

When should I use corrected calcium instead of ionized calcium?

Use corrected calcium when ionized calcium is not available; ionized calcium is preferred for definitive assessment, especially in critically ill patients.

Does the correction factor always use 0.8?

The 0.8 mg/dL per 1 g/dL albumin adjustment is commonly used, though some labs may apply slightly different factors based on local validation.

Are there limitations to this formula?

Yes. The formula is an estimate and can be inaccurate with abnormal binding proteins or severe illness; measure ionized calcium when precise values are required.