Corrected Sodium Calculator

How to calculate corrected sodium?

Glucose is an osmotically active substance that increases the osmolarity of the extracellular fluid. When blood sugar levels are high, water is drawn from the intracellular space into the extracellular space to balance the concentration. This additional water dilutes the sodium in the bloodstream, resulting in a measured sodium level that is lower than the actual concentration.

Formula: Na_corrected = Na_measured + [Factor * (Glucose - 100) / 100]

Using the Corrected Sodium calculator: an example

Consider a patient with a Measured Sodium of 130 mEq/L and a Glucose level of 500 mg/dL.

Step-by-step calculation:

• Calculate excess glucose: 500 - 100 = 400
• Divide by 100: 400 / 100 = 4
• Multiply by factor 1.6: 4 * 1.6 = 6.4
• Add to measured value: 130 + 6.4 = 136.4 mEq/L

Frequently Asked Questions

Why is this correction necessary?
It helps clinicians distinguish between true hyponatremia and dilutional (hypertonic) hyponatremia caused by high blood sugar, ensuring appropriate treatment.

When should I use the 2.4 factor?
A correction factor of 2.4 is often used when glucose levels exceed 400 mg/dL, as some clinical guidelines suggest it provides a more accurate estimate in cases of severe hyperglycemia.

Does this apply to other solutes?
No, this specific formula is designed specifically for the relationship between glucose and sodium. Other osmotically active agents like mannitol follow different correction principles.