Corrected Calcium Calculator Formula
Understand the math behind the corrected calcium calculator. Each variable explained with a worked example.
Formulas Used
Corrected Calcium
corrected_ca = total_calcium + 0.8 * (4.0 - albumin)Adjustment Amount
adjustment = 0.8 * (4.0 - albumin)Variables
| Variable | Description | Default |
|---|---|---|
total_calcium | Total Serum Calcium(mg/dL) | 8.5 |
albumin | Serum Albumin(g/dL) | 3 |
How It Works
Corrected Calcium Formula
Corrected Ca = Total Ca + 0.8 x (4.0 - Albumin)
About 40% of serum calcium is bound to albumin. When albumin is low, total calcium appears low even if ionized (active) calcium is normal.
Normal Ranges
Worked Example
Total calcium 8.5 mg/dL with albumin 3.0 g/dL.
- 01Adjustment = 0.8 x (4.0 - 3.0) = 0.8 mg/dL
- 02Corrected Ca = 8.5 + 0.8 = 9.3 mg/dL
- 03Within normal range (8.5-10.5)
Frequently Asked Questions
Why do we correct calcium for albumin?
About 40% of calcium in the blood is bound to albumin. When albumin is low (common in hospitalized patients), total calcium underestimates the true calcium status.
When is corrected calcium needed?
Corrected calcium should be calculated whenever albumin is below 4.0 g/dL. This is common in liver disease, malnutrition, nephrotic syndrome, and critical illness.
What causes high corrected calcium?
Hyperparathyroidism, malignancy, vitamin D excess, thiazide diuretics, and granulomatous diseases are common causes of elevated calcium.
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Open Corrected Calcium Calculator