Work out anion gap instantly with clear inputs, formula shown and shareable results.
Subtracts chloride and bicarbonate from sodium to give the anion gap, then corrects it for albumin, which carries most of the unmeasured anion charge.
Anion gap
AG = Na - (Cl + HCO3); albumin-corrected AG = AG + 2.5 x (4 - albumin g/dL)
Educational estimate only. Not a substitute for professional clinical judgement, and must not be used to make treatment or dosing decisions.
Some laboratories add potassium, which raises the reference range by about 4 mmol/L; the common form omits it.
Albumin is the largest unmeasured anion, so hypoalbuminaemia masks a genuinely raised gap.