[TOC]
- Quantitates unmeasured anions
- Every acid thats put into the system dissociates freely to let go of its hydrogen ion (e.g. lactic acid → H+ + Lactate)
- Specifically interested in anions of added acids (e.g. lactate, salicylates, ketoacids)
- Cation (measured) + Cation (unmeasured) = Anion (measured) + Anion (unmeasured)
- Measured cation = Na+
- Measured anion = Cl-, HCO3-
- Na+ + Cation (unmeasured) = (Cl- + HCO3-) + Anion (unmeasured)
- Na+ - (Cl- + HCO3-) = Anion (unmeasured) - Cation (unmeasured)
- Normal anion gap = 12
- Should be calculated in every circumstance to uncover potentially hidden complex disorders