Correct total serum calcium for low albumin with Payne’s formula in mg/dL or mmol/L, and see whether the corrected value is low, normal or high.
About this tool
Albumin-corrected calcium in mg/dL or mmol/L.
How to use Corrected Calcium Calculator
- Choose conventional (mg/dL, g/dL) or SI (mmol/L, g/L) units.
- Enter total calcium and serum albumin.
- Read the corrected calcium and its interpretation.
Worked example
Calcium 8.2 mg/dL with albumin 2.8 g/dL corrects to 9.16 mg/dL (2.29 mmol/L), which is within the normal range.
Why correct calcium for albumin?
About 40% of calcium is bound to albumin, so low albumin lowers total calcium while the active ionized calcium may be normal.
When should ionized calcium be measured instead?
In critical illness, kidney failure and acid–base disturbances the correction is unreliable, so measure ionized calcium directly.
References
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