Hillier Formula (preferred):
Corrected Na = Measured Na + 2.4 × [(Glucose mg/dL − 100) / 100]
or +1.6 for every 100 mg/dL above 100 (Katz method)
Corrected Sodium Calculator 2025: Hyperglycemia and Sodium Adjustment
Corrected sodium adjusts measured serum sodium for the diluting effect of hyperglycemia. High glucose draws water into the vascular space, falsely lowering sodium. This calculator uses the Hillier formula (2.4 mEq/L per 100 mg/dL) — more accurate than Katz (1.6).
Why Correct Sodium?
In DKA and HHS, glucose >400 mg/dL can lower sodium by 10–15 mEq/L. Uncorrected values mislead treatment. Corrected sodium guides fluid and insulin therapy.
Formulas Compared
| Formula | Correction Factor | Use Case |
|---|---|---|
| Hillier (1999) | 2.4 mEq/L per 100 mg/dL | Preferred; validated in ICU |
| Katz (1973) | 1.6 mEq/L per 100 mg/dL | Older; under-corrects |
Clinical Scenarios
- DKA: Corrected Na >145 → risk of cerebral edema with rapid correction
- HHS: Often severe hypernatremia when corrected
- Hyponatremia workup: Always correct for glucose before osmolarity
Interpretation Guide
- Corrected Na <135: True hyponatremia persists
- 135–145: Appropriate (euvolemic)
- >145: Risk of hypernatremia post-treatment
Limitations
- Not for mannitol, glycine, or maltose interference
- Less accurate at glucose >1000 mg/dL
- Does not account for triglycerides or proteins
Advanced Use
- Pair with Serum Osmolality and Anion Gap
- Recheck after every 100–200 mg/dL glucose drop
- Use in sodium correction rate: <8 mEq/L per 24h in chronic cases
FAQs
Should I use 1.6 or 2.4? Use 2.4 (Hillier) — more accurate in modern assays.
What if glucose is in mmol/L? Convert: mg/dL = mmol/L × 18.
Can I use this in pediatrics? Yes, same formula applies.
Conclusion
Use our 2025 Corrected Sodium Calculator in every hyperglycemic patient. Prevents over- or under-correction of fluids. Always verify with repeat labs.
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