Corrected Sodium (Hyperglycaemia)

Enter measured sodium, serum glucose, and an optional correction factor to estimate the corrected sodium concentration.

Measured sodium (mEq/L)

Serum glucose (mg/dL)

Correction factor (mEq/L per 100 mg/dL)

Typical factor 1.6; use 2.4 in profound hyperglycaemia per institutional preference.

Corrected sodium

134.8 mEq/L

Correction amount

+4.8 mEq/L

The corrected sodium accounts for sodium dilution by hyperglycaemia. Use this value to assess true tonicity and guide fluid therapy. Reduce correction factor to 2.4 mEq/L per 100 mg/dL in severe hyperglycaemia if local practice dictates.

How to Use This Calculator

Confirm hyperglycaemia

Use this adjustment when glucose exceeds 100 mg/dL and dilutional hyponatraemia is suspected.

Input sodium and glucose

Provide measured sodium (mEq/L) and serum glucose (mg/dL). Adjust the correction factor if your protocol differs.

Use corrected sodium clinically

Assess tonicity and guide fluid therapy (e.g., free water replacement). Monitor sodium as glucose corrects to avoid rapid shifts.

Formula

Corrected Na⁺ = Measured Na⁺ + Correction factor × ((Glucose − 100) ÷ 100)

Standard correction factor = 1.6 mEq/L per 100 mg/dL glucose above 100 mg/dL.

Full Description

Hyperglycaemia draws water from intracellular to extracellular space, diluting serum sodium. Corrected sodium reflects the underlying tonicity by accounting for this shift. Calculating corrected sodium prevents misclassification of hyponatraemia and aids in planning fluid therapy for diabetic ketoacidosis or hyperosmolar hyperglycaemic state. Once glucose normalises, measured sodium approximates corrected values; monitor electrolytes frequently during therapy.

Frequently Asked Questions

Why 1.6 mEq/L per 100 mg/dL?

The Katz formula estimates sodium falls ~1.6 mEq/L for every 100 mg/dL glucose increase above 100. Some studies support 2.4 mEq/L in severe hyperglycaemia.

When should I use 2.4?

Consider 2.4 mEq/L in marked hyperglycaemia (>400–500 mg/dL) or per institutional policy. Adjustable factor lets you tailor the calculation.

Does this apply to hyponatraemia from other causes?

No. It only corrects dilutional hyponatraemia due to hyperglycaemia. For other etiologies, use appropriate diagnostic algorithms.

How often should sodium be rechecked?

In DKA/HHS, monitor electrolytes every 2–4 hours during therapy to avoid rapid shifts and guide fluid/electrolyte replacement.