ACID BASE DISORDERS-ANION GAP

SUMMARY

1. Formula: AG = Na⁺- (HCO₃^- + Cl^-)

2. AG is a indication of the unmeasured anions (mostly albumin).

3. Any change in this gap is due to added anions such as ketones or lactate.

4. This gap is commonly taught as the "anion gap" rather than the "unmeasured anions minus the unmeasured cations gap"!

5. The anion gap is usually about 10 mEq/L (+/- 3).

6. An elevated anion gap means an increased H⁺, which always means metabolic acidosis.

Reference(s)

Wilkinson, I. (2017). Oxford handbook of clinical medicine. Oxford: Oxford University Press.
Hannaman, R. A., Bullock, L., Hatchell, C. A., & Yoffe, M. (2016). Internal medicine review core curriculum, 2017-2018. CO Springs, CO: MedStudy.
Therapeutic Guidelines. Melbourne: Therapeutic Guidelines Limited. https://www.tg.org.au [Accessed 2021].