Corrected Sodium Calculator

This calculator adjusts your sodium level for high blood sugar:

• When your glucose spikes above 5.5 mmol/L, it creates an osmotic pull that drags water from your cells into your bloodstream.
• The calculator uses the Katz formula - it adds 1.6 mmol/L to sodium for every 5.5 mmol/L glucose above normal.

Hyperglycaemia pulls water out of cells and lowers your measured sodium value:

• Glucose can't cross cell membranes easily, so it stays in your bloodstream and creates osmotic pressure.
• This pressure pulls water from cells into blood, diluting all dissolved minerals including sodium.
• The sodium isn't lost - it's just spread thinner.

The corrected value shows your "true" sodium once glucose is normal:

• As insulin treatment lowers your glucose, the extra water returns to your cells and your sodium concentration naturally rises. The corrected sodium predicts where your level will land once glucose normalises.

Understanding the formula:

• Corrected Na (mmol/L) = Na + 1.6 × ((glucose − 5.5) / 5.5)
• Example 1:
  • Measured sodium: 130 mmol/L; Glucose: 20 mmol/L
  • Correction: 1.6 × ((20 − 5.5) / 5.5) = 4.2 mmol/L
  • Corrected Na = 134.2 mmol/L
• If hypoalbuminaemia is present, consider checking the 
  Corrected Calcium Calculator to adjust calcium levels appropriately.
  

1. Enter measured sodium in mmol/L.
2. Enter serum glucose in mmol/L.
3. Click "Calculate" to see results. 
4. If you need to redo, click "Reset" to start fresh.

**All information is private, no data is saved or shared.**

Q1. When is sodium correction most critical?

• When glucose floods your bloodstream, it can't easily enter cells, so it accumulates and drags water from cells into the bloodstream.
• This extra water volume dilutes the sodium concentration, making it appear low even though total body sodium remains unchanged. Same sodium spread through more fluid.
• For patients with mixed acid-base disorders, you may also find the 
  Anion Gap Calculator useful to assess concurrent metabolic disturbances.

Q2. When is sodium correction most critical?

• Diabetic ketoacidosis (DKA) - Diabetic emergency with high glucose and acid blood.
• Hyperosmolar state (HHS) - Diabetic emergency with extreme glucose but normal pH.
• DKA and HHS represent the most dramatic examples of sodium distortion. With glucose levels 3-6 times normal, sodium readings can be depressed by 4-10 mmol/L.
• This makes patients appear profoundly hyponatraemic when they're actually dehydrated. Correction becomes essential when glucose exceeds 11 mmol/L in symptomatic patients.

Q3. Why use 1.6 mmol/L correction instead of 2.4?

• The debate centres on how much water glucose actually pulls into blood.
• Katz's original research found 1.6 mmol/L correction per 5.5 mmol/L glucose rise, while Hillier's later study suggested 2.4 mmol/L.
• Katz is more commonly used as it's more conservative and prevents overcorrection.