Sodium Correction (Hyperglycemia)

Correct measured serum sodium for elevated glucose. High glucose draws water intravascularly, diluting sodium — the true sodium is higher than measured.

Indication

Correct measured serum sodium for elevated glucose. High glucose draws water intravascularly, diluting sodium — the true sodium is higher than measured.

Criteria

id: na; label: Measured sodium (mEq/L); type: number; placeholder: e.g. 130
id: glucose; label: Glucose (mg/dL); type: number; placeholder: e.g. 600

Clinical pearls

The Katz correction (1.6 per 100 mg/dL) underestimates true sodium at very high glucose levels
Hillier correction (2.4) is more accurate above 400 mg/dL — use it in DKA with glucose >600
Corrected Na helps assess true fluid status in DKA
Corrected sodium rising despite treatment suggests inadequate free water replacement

Source and review

Hillier TA et al. Am J Med 1999; Katz MA. NEJM 1973. Last reviewed: 2025-01-01