Calculators · Endocrinology · Formula

Corrected sodium in hyperglycaemia (Katz 1.6 and Hillier 2.4)

Also called glucose-corrected sodium, Katz correction, Hillier correction

Sodium expected once hyperglycaemia is corrected, by both classic correction factors.

mmol/L

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Formula and scoring

Corrected Na = measured Na + k × (glucose − 100)/100, glucose in mg/dL; k = 1.6 (Katz 1973) or 2.4 (Hillier 1999).

Exam and ward pearls

  • A "normal" sodium in severe hyperglycaemia usually hides hypernatraemia once corrected — common in HHS.
  • ADA 2024 notes that a 100 mg/dL fall in glucose raises sodium by about 1.6 mmol/L during treatment.

When not to rely on it

  • Hillier found the relation non-linear above 400 mg/dL (a factor of 4.0 fitted better there); both factors are approximations. Correction is applied only to glucose above 100 mg/dL.

Source

  1. Katz MA. Hyperglycemia-induced hyponatremia: calculation of expected serum sodium depression. N Engl J Med. 1973;289(16):843-4. doi:10.1056/NEJM197310182891607 · PMID 4763428
  2. Hillier TA, Abbott RD, Barrett EJ. Hyponatremia: evaluating the correction factor for hyperglycemia. Am J Med. 1999;106(4):399-403. doi:10.1016/s0002-9343(99)00055-8 · PMID 10225241
  3. Umpierrez GE, Davis GM, ElSayed NA, et al. Hyperglycemic crises in adults with diabetes: a consensus report. Diabetes Care. 2024;47(8):1257-1275. Figure 2 and Table 2. doi:10.2337/dci24-0032 · PMID 39052901

Formula and cut-offs checked against these sources on 8 Nov 2026. Educational tool for clinicians; it does not replace clinical judgement.

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