Sodium Correction Calculator
Correct measured serum sodium for hyperglycemia. Essential for accurate assessment in diabetic emergencies (DKA, HHS) where glucose-induced osmotic shifts cause dilutional hyponatremia.
Normal range: 135-145 mEq/L
Correction applies when glucose >100 mg/dL (5.6 mmol/L)
Why Correct Sodium?
High glucose pulls water from cells into blood, diluting sodium concentration. The measured sodium appears lower than it actually is. Correcting reveals the true sodium status.
Understanding Sodium Correction
Hyperglycemia causes osmotic movement of water from intracellular to extracellular space, diluting serum sodium. The measured sodium is falsely low - correcting it reveals the true sodium status for proper clinical management.
Sodium Categories
Correction Formulas
Corrected Na = Measured Na + 1.6 × [(Glucose - 100) / 100]Corrected Na = Measured Na + 2.4 × [(Glucose - 100) / 100]Frequently Asked Questions
Use the Katz formula (1.6 factor) for glucose levels up to 400 mg/dL. For glucose >400 mg/dL (common in HHS), the Hillier formula (2.4 factor) is more accurate as it accounts for the greater osmotic shift at extreme glucose levels. Some sources suggest using 2.4 for all corrections.
As glucose falls with insulin treatment, water shifts back into cells and measured sodium rises. For every 100 mg/dL decrease in glucose, expect sodium to increase by 1.6-2.4 mEq/L. Monitor electrolytes every 2-4 hours. The sodium should approach the corrected value as euglycemia is restored.
This correction applies specifically to hyperglycemia. It doesn't account for other causes of pseudohyponatremia (hyperlipidemia, hyperproteinemia) or conditions with both hyperglycemia and independent sodium disorders. Clinical correlation and serial monitoring are essential.
In DKA (glucose 250-600 mg/dL), corrected sodium is often normal or mildly low. In HHS (glucose often >600 mg/dL), corrected sodium frequently reveals significant hypernatremia due to profound dehydration. HHS patients typically have larger water deficits requiring more aggressive fluid replacement.
Limit sodium changes to 8-10 mEq/L per 24 hours if starting from severe hyponatremia (<120) to prevent osmotic demyelination syndrome. In diabetic emergencies, the glucose correction itself drives sodium changes. Slow glucose correction (50-70 mg/dL/hr) helps control the sodium rise. For hypernatremia, limit correction to 10-12 mEq/L per 24 hours.
Clinical Reminders
- Trend matters: Serial measurements more important than single values
- Check potassium: K+ shifts occur with insulin; replace early in DKA/HHS
- Calculate osmolality: Helpful for confirming HHS (often >320 mOsm/kg)
- Fluid choice: Start with 0.9% NS; switch to 0.45% NS when sodium normalizes
Medical Disclaimer: This calculator provides estimates for educational purposes. Management of diabetic emergencies requires clinical judgment, frequent monitoring, and consideration of individual patient factors. Always consult current guidelines and clinical expertise.