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Corrected Calcium Calculator
Hematology / Electrolytes
Total serum calcium is bound to albumin. When albumin is low, measured calcium underestimates true calcium. This calculator corrects total calcium for hypoalbuminemia using the Payne formula.
Formula
Corrected Ca = Measured Ca + 0.8 × (4.0 − Albumin)
Ionized Ca ≈ Corrected Ca / 2.0 (estimate only)
Ionized Ca ≈ Corrected Ca / 2.0 (estimate only)
Reference
| Condition | Corrected Calcium | Notes |
|---|---|---|
| Severe Hypocalcemia | <7.5 mg/dL | Tetany, seizures risk |
| Hypocalcemia | 7.5–8.5 mg/dL | Symptoms may occur |
| Normal | 8.5–10.5 mg/dL | — |
| Hypercalcemia | 10.5–12 mg/dL | — |
| Significant Hypercalcemia | 12–14 mg/dL | Urgent evaluation |
| Hypercalcemic Crisis | >14 mg/dL | Emergency |
Clinical Notes
Hypocalcemia causes: Hypoparathyroidism, vitamin D deficiency, pancreatitis, CKD, magnesium deficiency, bisphosphonates.
Hypercalcemia causes: Primary hyperparathyroidism (most common outpatient), malignancy (most common inpatient), vitamin D toxicity, sarcoidosis, thiazide diuretics, milk-alkali syndrome.
Hypercalcemia causes: Primary hyperparathyroidism (most common outpatient), malignancy (most common inpatient), vitamin D toxicity, sarcoidosis, thiazide diuretics, milk-alkali syndrome.
For educational use only. Clinical decisions must incorporate full patient evaluation.
