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Calculate serum anion gap from electrolytes for acid-base analysis. Enter sodium, chloride, bicarbonate, and optional potassium for AG interpretation.
Estimate creatinine clearance with Cockcroft-Gault equation for drug dosing. Enter age, weight, sex, and serum creatinine for kidney function assessment.
Calculate IV drip rate in drops per minute and mL per hour. Enter volume, time, and drop factor for manual gravity drip rate nursing calculations.
Standard Payne formula assuming normal albumin 4.0 g/dL. Each 1 g/dL albumin drop adds 0.8 mg/dL to corrected calcium.
Corrected Ca = Measured Ca + 0.8 × (4.0 − Albumin g/dL)Compare corrected value to lab reference. Symptomatic hypocalcemia may occur at low-normal levels with rapid drops.
Normal ≈ 8.5–10.5 mg/dL (2.1–2.6 mmol/L)When ionized calcium measured directly, correction formula is unnecessary. Use in ICU and pH abnormalities.
Ionized Ca is gold standard when available — not estimated by correctionUpdated: July 2026
Ca 7.8, albumin 2.0: Corrected = 7.8 + 0.8×(2) = 9.4 mg/dL — normal, no treatment needed.
Ca 7.5, albumin 4.0: Corrected 7.5 — true hypocalcemia. Check magnesium, PTH, vitamin D.
In sepsis or transfusion, albumin correction unreliable. Order ionized calcium for treatment decisions.
Estimate physiologically active calcium when albumin is abnormal using the albumin correction formula. Enter total serum calcium and albumin to get corrected calcium — essential when interpreting labs in critically ill or malnourished patients.