Anion Gap
Anion Gap - a deterministic tool in Sophie Well's Clinical Math & Conversions group.
Open the Anion Gap → Runs in your browser. No signup, no tracking.
What this is
Compute the anion gap (Na - (Cl + HCO3)) and the albumin-corrected anion gap (+2.5 mEq/L per 1 g/dL drop below 4.0). Sophie Well returns both values so a low albumin doesn't mask a real high-anion-gap metabolic acidosis. Source: Emmett & Narins, Medicine 1977; Figge et al., Crit Care Med 1998.
When to use it
Use this on any chemistry panel that shows acidosis, when MUDPILES is on the differential, or when albumin is significantly low and the uncorrected gap looks deceptively normal. The Anion Gap & Delta-Delta tile extends this with the delta-gap / delta-bicarb ratio for mixed disorders.
References
Emmett M, Narins RG. Clinical use of the anion gap. Medicine (Baltimore). 1977;56(1):38-54.
Worked example: AG 16; corrected AG 16
Sophie Well is a reference and educational tool. Not medical, legal, or financial advice. Does not replace clinician judgment, professional billing review, or legal counsel.