Sodium Correction for Hyperglycemia

In patients with hyperglycemia, serum sodium levels often appear deceptively low due to osmotic water shifts from the intracellular to extracellular compartment, causing dilutional or pseudohyponatremia. To distinguish true hyponatremia from pseudohyponatremia, clinicians apply a correction formula for serum sodium that accounts for elevated glucose levels. Traditionally, the correction factor has been 1.6 mEq/L to 2.4 mEq/L sodium increase for every 100 mg/dL rise in serum glucose. Clinicians should act on the corrected sodium level, not the unadjusted measurement, when guiding management decisions. Initial workup should also include serum osmolality to rule out an osmolality gap that may contribute to pseudohyponatremia. Monitoring of sodium levels is essential during treatment, as levels can shift rapidly with fluid replacement and glucose control. In cases of extreme hyperglycemia, corrected sodium levels may unmask true hyponatremia, which is associated with poorer clinical outcomes and may inform prognosis. Therefore, frequent laboratory reassessment is recommended, with the interval depending on the severity of the electrolyte and glucose abnormalities. Current literature continues to support the use of sodium correction formulas, and some studies have linked the degree of corrected hyponatremia with patient mortality, underscoring its clinical relevance in managing hyperglycemic patients.