Corrected Calcium Calculator
About half of the calcium in blood is bound to albumin. When albumin is low, total calcium can look falsely low. This calculator adjusts it using the widely used Payne formula.
For information only. A calculator cannot diagnose you; discuss your results with your doctor.
Good to know
Formulas: mg/dL: calcium + 0.8 × (4.0 − albumin in g/dL); mmol/L: calcium + 0.02 × (40 − albumin in g/L). Many labs use their own version, so your report may differ slightly. The correction is less reliable in kidney failure and in very ill patients; ionised calcium is the most accurate test then.
Formula
mg/dL: corrected Ca = Ca + 0.8 × (4.0 − albumin in g/dL)
mmol/L: corrected Ca = Ca + 0.02 × (40 − albumin in g/L)
Common questions
What is the corrected calcium formula?
In mg/dL: calcium + 0.8 × (4.0 − albumin in g/dL). In mmol/L: calcium + 0.02 × (40 − albumin in g/L).
When is corrected calcium not reliable?
In kidney failure and in very ill patients; ionised calcium is the most accurate test then.
Why does my lab's corrected calcium differ slightly?
Many labs use their own version of the formula.