Hyperglycemia-Corrected Sodium CalculatorFree online fitness & health calculator — instant results, no sign-up
Estimate corrected sodium using the Katz hyperglycemia adjustment.
For general information only. This is not medical advice, diagnosis, dosing guidance or a treatment recommendation. Talk to a doctor or other qualified health professional about your health, pregnancy, or diet.
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About the Hyperglycemia-Corrected Sodium Calculator
The Hyperglycemia-Corrected Sodium Calculator estimates adult serum sodium after accounting for the sodium-lowering effect of elevated blood glucose. It uses the Katz adjustment, adding 1.6 mmol/L to measured sodium for each 100 mg/dL of glucose above 100 mg/dL. This educational estimate is not a diagnosis or treatment recommendation.
- Measured sodium (mmol/L)
- The sodium concentration reported by a blood test, in mmol/L, with a default value of 132.
- Glucose (mg/dL)
- The blood glucose concentration associated with the sodium measurement, in mg/dL, with a default value of 300.
Formula and method
Na_corrected = Na_measured + 1.6 × ((G − 100) / 100)
- Na_correctedEstimated sodium concentration corrected for hyperglycemia, in mmol/L.
- Na_measuredMeasured blood sodium concentration, in mmol/L.
- GBlood glucose concentration, in mg/dL.
- 100The reference glucose concentration is 100 mg/dL; the denominator expresses the glucose difference in increments of 100 mg/dL.
- 1.6The Katz correction factor: 1.6 mmol/L of sodium per 100 mg/dL glucose above the reference concentration.
Subtract the reference glucose of 100 mg/dL from the entered glucose, divide the difference by 100 mg/dL, and multiply by the Katz factor of 1.6 mmol/L. Add this adjustment to the measured sodium. With the default inputs, the adjustment is 1.6 × ((300 − 100) / 100) = 3.2 mmol/L, giving 132 + 3.2 = 135.2 mmol/L.
Worked example
These are the calculator's starting values and the results it actually produces for them.
Inputs
- Measured sodium132 mmol/L
- Glucose300 mg/dL
Results
- Corrected sodium (Katz)135.2 mmol/L
- NoteUses 1.6 mmol/L per 100 mg/dL glucose above 100; alternative factors exist.
- NoteEducational estimate for adults; not a diagnosis or treatment recommendation.
How to use the Hyperglycemia-Corrected Sodium Calculator
- 1Enter the measured sodium in mmol/L; the default is 132.
- 2Enter the associated blood glucose in mg/dL; the default is 300, and glucose in mmol/L must be converted before entry.
- 3Check that the measurements reflect the same clinical time point and that both units are correct.
- 4Run the calculation and read the corrected sodium result; the default inputs produce 135.2 mmol/L.
- 5Read both note rows and discuss clinically concerning laboratory results with a qualified healthcare professional rather than using this estimate to choose treatment.
Reading your result
The “Corrected sodium (Katz)” row reports the estimated sodium after the Katz hyperglycemia adjustment: 135.2 mmol/L for measured sodium of 132 mmol/L and glucose of 300 mg/dL. It does not replace the measured sodium or guarantee what a future blood test will show. The first “Note” row states: “Uses 1.6 mmol/L per 100 mg/dL glucose above 100; alternative factors exist.” The second “Note” row states: “Educational estimate for adults; not a diagnosis or treatment recommendation.” Interpret the estimate alongside the laboratory reference range, symptoms, and other clinical findings.
Limitations
The Katz formula assumes a fixed, linear relationship between elevated glucose and its effect on measured sodium; individual responses can differ, particularly with marked hyperglycemia. Alternative correction factors exist and can yield different estimates. This tool is intended for adult hyperglycemia, not for interpreting low glucose or providing pediatric guidance. It does not account for ongoing fluid or electrolyte losses, kidney function, treatment effects, or laboratory artifacts, and it cannot diagnose a hyperglycemic emergency or determine fluid, insulin, or sodium treatment.
Common questions
Why does elevated glucose lead to a sodium correction?+
Elevated extracellular glucose draws water out of cells, which can dilute sodium in the blood. The Katz adjustment estimates sodium after accounting for this water-shift effect; it does not measure total body sodium.
Why do the default inputs produce 135.2 mmol/L?+
Glucose of 300 mg/dL is 200 mg/dL above the 100 mg/dL reference. The Katz adjustment is therefore 1.6 × 2 = 3.2 mmol/L, which is added to the measured sodium of 132 mmol/L to obtain 135.2 mmol/L.
Why might another corrected sodium calculator give a different result?+
Another calculator may use a different correction factor, such as 2.4 mmol/L per 100 mg/dL, rather than the Katz factor of 1.6 used here. Compare the stated formulas before comparing results; the appropriate clinical interpretation depends on the patient's circumstances.
Does the corrected sodium tell me how much sodium or fluid to take?+
No. Corrected sodium is an interpretive estimate, not a dosing guide or a measure of sodium deficit. Fluid and electrolyte decisions require clinical assessment, including measured laboratory values, hydration status, kidney function, and the cause of hyperglycemia.
Does the calculator save my information?+
Calculations run in your browser. While signed in, inputs and results are automatically recorded in account history; saving a result creates a separate saved record.
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Results are estimates for informational purposes and are not financial, medical or legal advice.