Corrected Sodium

Corrects serum sodium for hyperglycemia using the conventional correction factor. Hyperglycemia draws water into the extracellular space, diluting sodium; this correction estimates what sodium would be at a normal glucose level.

Internal Medicine Internal MedicineEvidence-BasedUpdated 2026-08-06

Clinical Notes

Formula

Corrected Sodium = Measured Sodium + 1.6 × (Glucose − 100) / 100

Normal Range

135–145 mmol/L

Clinical Notes

Interpret results together with the patient's clinical presentation.

References

MedCalcHub Clinical References

Calculator Information

Specialty

Internal Medicine

📋 Reference Ranges

Normal Range

135–145 mmol/L

Reference ranges for this calculator
Classification	Range
Hyponatremia (corrected)	<134.1
Normal corrected sodium	135–145
Hypernatremia (corrected)	≥146
Severe hypernatremia	≥160

What This Calculator Measures

Corrects the measured serum sodium for hyperglycemia to reveal the true sodium status in patients with significant glucose elevation.

How to Use

Enter the measured serum sodium in mmol/L.
Enter the serum glucose in mg/dL.
Review the corrected sodium value.

Interpretation Guide

Corrected sodium accounts for the dilutional effect of glucose. For every 100 mg/dL increase in glucose above 100 mg/dL, sodium decreases by approximately 1.6 mmol/L. A normal corrected sodium with a low measured sodium indicates true dilutional hyponatremia.

Clinical Significance

In hyperglycemic states, water shifts from the intracellular to the extracellular space, diluting serum sodium. Without correction, the true sodium status may be masked, leading to inappropriate fluid management.

When to Use

Diabetic ketoacidosis (DKA)
Hyperosmolar hyperglycemic state (HHS)
Any condition with significant hyperglycemia
Interpretation of sodium in uncontrolled diabetes

When Not to Use

When glucose is normal or only mildly elevated
As a replacement for clinical assessment of fluid status

Limitations

The correction factor (1.6 mmol/L per 100 mg/dL glucose) is an approximation.
May be less accurate at very high glucose levels (>600 mg/dL).
Does not account for other osmotic agents (mannitol, glycine).
Should be used alongside clinical assessment of volume status.

Worked Example

A 58-year-old woman with DKA has a measured sodium of 128 mmol/L and glucose of 500 mg/dL.

Inputs:

sodium: 128

glucose: 500

Corrected sodium ≈ 128 + 1.6 × (500−100)/100 = 128 + 6.4 = 134.4 mmol/L. The corrected value remains mildly low, showing that glucose-driven dilution accounts for a large part (6.4 mmol/L) of the measured fall.

Evidence

Source: Endocrinology / Nephrology
Reference: Hillier TA, Abbott RD, Barrett EJ. Hyponatremia: evaluating the correction factor for hyperglycemia. Am J Med. 1999;106:399-403.
Reviewed By: MedCalcHub Clinical Team
Version: 1.0
Updated: 2026-08

Hillier TA, Abbott RD, Barrett EJ. Am J Med. 1999;106:399-403.

References

Hillier TA, Abbott RD, Barrett EJ. Hyponatremia: evaluating the correction factor for hyperglycemia. Am J Med. 1999;106:399-403. (Level II)

Frequently Asked Questions

Why does hyperglycemia lower sodium?

High glucose increases serum osmolality, drawing water from the intracellular to the extracellular space. This dilutes the serum sodium, causing a falsely low measured value. The corrected sodium estimates what the sodium would be at a normal glucose.

What correction factor should I use?

The conventional correction factor is 1.6 mmol/L for every 100 mg/dL increase in glucose above 100 mg/dL. For very high glucose (> 400 mg/dL), some experts use a factor of 2.0–2.4.

When should I correct sodium for glucose?

Correct sodium whenever glucose is significantly elevated (> 200 mg/dL), especially in diabetic ketoacidosis (DKA) and hyperosmolar hyperglycemic state (HHS), to accurately assess the patient's true sodium status.

Disclaimer: This calculator is intended for educational and clinical decision support purposes only. Sodium correction is an approximation and should be interpreted alongside clinical assessment of the patient's volume and glucose status.