Corrected Calcium Calculator

Calculate corrected calcium levels based on serum albumin using standard clinical formulas for accurate calcium assessment in hypoalbuminemia

Clinical Scenarios

Total Calcium

Reference: 8.5-10.5 mg/dL (2.12-2.62 mmol/L)

Serum Albumin

Reference: 3.5-5.0 g/dL (35-50 g/L)

Correction Formula

Most commonly used: Corrected Ca = Total Ca + 0.8 × (4.0 - Albumin)

Why Correct Calcium?

About 40-45% of calcium is bound to albumin. When albumin is low, total calcium appears low even if ionized calcium is normal.

When to Use:

• Hypoalbuminemia (albumin < 3.5 g/dL)

• Suspected calcium disorders

• Critical care monitoring

• When ionized calcium unavailable

Limitations:

• pH and protein binding changes affect accuracy

• Ionized calcium remains gold standard

• Less reliable in critical illness

Normal Ranges:

• Total Calcium: 8.5-10.5 mg/dL

• Ionized Calcium: 4.6-5.3 mg/dL

• Serum Albumin: 3.5-5.0 g/dL

Correction Formulas:

• Standard: Ca + 0.8 × (4.0 - Albumin)

• Modified: Ca + 0.8 × (4.4 - Albumin)

• Pediatric: Ca + 0.02 × (40 - Albumin g/L)

Clinical Actions:

• Hypocalcemia: Check PTH, Vitamin D, Mg

• Hypercalcemia: Investigate malignancy, PTH

• Always correlate with symptoms