Corrected Calcium Calculator
Calculate the albumin-corrected serum calcium level using the standard correction formula. About 40% of blood calcium is bound to albumin, so low albumin levels can make total calcium appear falsely low.
Approximately 40% of total serum calcium is bound to albumin, 10% is bound to other anions, and 50% is the physiologically active ionized (free) calcium. When albumin levels are low (hypoalbuminemia), the total calcium measurement will be artificially decreased even though the ionized calcium may be normal. The correction formula adjusts for this protein binding effect.
The standard formula is: Corrected Calcium = Total Calcium + 0.8 x (4.0 - Albumin). For every 1 g/dL decrease in albumin below 4.0, the total calcium is adjusted upward by 0.8 mg/dL. This correction helps clinicians determine whether a patient with low albumin truly has hypocalcemia or if the low total calcium is simply an artifact of low protein binding.
IMPORTANT DISCLAIMER: This calculator is for educational purposes only. The corrected calcium formula is an approximation and may not be accurate in all clinical situations (e.g., critically ill patients, those with acid-base disturbances). Ionized calcium measurement is the gold standard when accurate assessment is needed. Always consult a healthcare provider for interpretation of lab results.