Corrected Calcium
Approximately 45% of serum calcium is bound to albumin. In states of hypoalbuminemia (e.g., malnutrition, liver disease, severe infection), the measured total calcium appears falsely low, while the physiologically active ionized calcium remains normal. This formula adjusts for albumin variance.
Results
mmol/L
*Standard reference range is typically 2.20 - 2.60 mmol/L.
Note: When albumin drops below 20 g/L, this formula becomes inaccurate. Direct measurement of ionized calcium via arterial/venous blood gas is strongly recommended.
Formula
Corrected Ca =
Total Ca + 0.02 × (40 - Albumin)
Total Ca + 0.02 × (40 - Albumin)
This formula assumes a normal albumin of 40 g/L. For every 1 g/L decrease in albumin below 40, the total calcium decreases by 0.02 mmol/L.
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