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Corrected Sodium (Glucose) Calculator

Calculate the glucose-corrected serum sodium to reveal true body tonicity in hyperglycemia. Classic Katz (1973) formula Na_corr = Na + 1.6 × (Glucose − 100)/100 (glucose mg/dL), or Hillier (1999) Na_corr = Na + 2.4 × (Glucose − 100)/100 which is more accurate at very high glucose (Katz tends to underestimate). Glucose unit selectable: mg/dL or mmol/L (reference 5.5 mmol/L). Hyperglycemia shifts water extracellularly and dilutes sodium; the corrected value reflects the real water balance. Corrected Na < 135 indicates true hyponatremia (DKA/HHS with free-water excess, SIADH, GI/renal losses); > 145 indicates true hypernatremia (common in HHS, signals free-water deficit and guides replacement). Derived from Katz NEJM 1973, Hillier 1999, Adrogué NEJM 2000, and MDCalc. Not medical advice.