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., Furmedge, D. and Sinharay, R. (2017). Oxford handbook of clinical medicine. Oxford: Oxford University Press. Get it on Amazon.
Feather, A., Randall, D. and Waterhouse, M. (2020). Kumar And Clark’s Clinical Medicine. 10th ed. S.L.: Elsevier Health Sciences. Get it on Amazon.
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].
