How this calculator works
Glucose is converted to mg/dL, then the two published coefficients are displayed separately. Katz used a theoretical coefficient of 1.6; Hillier found an overall mean of 2.4 in six healthy volunteers, with nonlinearity at high glucose. These estimates do not predict every patient's response or provide a sodium treatment target. The result is an estimate for information only and is not medical advice.
Formula
Corrected Na = measured Na + c × (glucose in mg/dL - 100)/100, where c is 1.6 for Katz or 2.4 for the overall Hillier estimate. Glucose mg/dL = mmol/L × 18.0156.
Worked example
Na 130 mmol/L and glucose 300 mg/dL give Katz 133.2 and Hillier 134.8 mmol/L. At glucose 100 mg/dL, both return the measured sodium unchanged.
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Frequently asked questions
Why give two results?
The coefficients come from different approaches and need not agree. The selector chooses which equation is rearranged in inverse modes.
Is the Hillier correction a piecewise rule here?
No. This page explicitly uses the published overall 2.4 coefficient. It does not silently switch coefficients above 400 mg/dL.
Does this correct lipid interference?
No. Hyperglycaemia shifts water between compartments; analytical pseudohyponatraemia from lipids is a different problem.