How this calculator works
The equation adjusts measured total magnesium to an albumin concentration of 40 g/L. Select the units before entering each number. Albumin in g/dL is multiplied by 10. The adjusted value remains an estimate of total concentration; it is not a measurement of the ionized fraction. The result is an estimate for information only and is not medical advice.
Formula
Adjusted magnesium (mmol/L) = measured magnesium + 0.005(40 - albumin in g/L). mg/dL = mmol/L × 2.4305.
Worked example
Measured magnesium 0.7 mmol/L with albumin 30 g/L gives 0.750 mmol/L. At albumin 40 g/L, the adjustment is zero.
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Frequently asked questions
Is this an ionized concentration?
No. Protein binding and pH affect the ionized fraction. Use an appropriate laboratory measurement when clinically indicated.
Can the adjustment lower the result?
Yes. The cited equation subtracts a correction when albumin exceeds 40 g/L.
How are mg/dL values converted?
The calculation uses the molar mass of magnesium. The same SI equation is used after conversion, avoiding inconsistent constants between unit systems.