Corrected Sodium Calculator
What is Corrected Sodium Calculator
The corrected sodium calculator adjusts a measured serum sodium for the diluting effect of a high glucose. When blood sugar rises, water shifts into the bloodstream and drags the sodium reading down, so the lab value looks lower than the true sodium. It adds back that dilutional drop using the 1.6 factor by default, or the 2.4 factor for very high glucose, per 100 mg/dL above normal.
How to use
- Enter the measured sodium in mmol/L.
- Enter the glucose and pick its unit, mg/dL or mmol/L.
- Choose the correction factor, 1.6 or 2.4.
- Read the corrected sodium and whether it is low, normal or high.
When to use it
A patient in diabetic ketoacidosis has a sodium of 130 with a glucose of 600 mg/dL, and you want the real sodium? Enter those numbers with the 1.6 factor and the corrected sodium comes out at 138 mmol/L, actually normal. It stops a pseudohyponatraemia from being mistaken for true low sodium, which changes how you think about fluids and the free water deficit.
Frequently asked questions
Which correction factor should I use?
The 1.6 factor per 100 mg/dL above 100 is the traditional choice and works well across most glucose levels. The 2.4 factor better fits very high glucose, above roughly 400 mg/dL, so pick the one your protocol favours.
Why does high glucose lower sodium?
Glucose is osmotically active. As it rises it pulls water out of cells into the blood, diluting the sodium. This is a real dilution, so the measured sodium is genuinely low even though total body sodium may be unchanged.
What is a normal sodium range?
Serum sodium is usually reported as 135 to 145 mmol/L. This tool flags the corrected value against that band, but always read it alongside the clinical picture and your own laboratory range.
Can I share this tool with my inputs pre-filled?
Yes. The URL updates automatically as you type. Copy it from the address bar or use the Copy link button, and anyone who opens the link will see your exact inputs ready to go.
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