- This is the difference between the cations and anions in the extracellular space and these are in routine calculated in the lab.
- Anion gap = (sodium + potassium) — (chloride + bicarbonate)
- Some lab don’t include potassium in the calculations.
- 16 + – 4 meq/L (if Potassium used in the calculation)
- 12 + – 4 meq/L (if potassium is excluded)