in failure to detect an accumulation of unmeasured anions. In the largest study published to date, featuring over 12,000 data sets, Figge, Bellomo and Egi demonstrated that the anion gap, when used to detect critical levels of lactate (greater than 4 mEq/L), exhibited a sensitivity of only 70.4%. In contrast, the albumin-corrected anion gap demonstrated a sensitivity of 93.0%. Therefore, it is important to correct the calculated value of the anion gap for the concentration of albumin, particularly in critically ill patients. Corrections can be made for the albumin concentration using the Figge-Jabor-Kazda-Fencl equation to give an accurate anion gap calculation as exemplified below. Sample calculations Given the following data from a patient with severe hypoalbuminemia suffering from postoperative multiple organ failure, calculate the anion gap and the albumin-corrected anion gap. Data: [Na+] = 137 mEq/L; [Cl−] = 102 mEq/L; [HCO] = 24 mEq/L; [Normal Albumin] = 4.4 g/dL; [Observed Albumin] = 0.6 g/dL. Calculations: Anion Gap = [Na+] - ([Cl−] + [HCO]) = 137 - (102 + 24) = 11 mEq/L. Albumin-Corrected Anion Gap = Anion Gap + 2.5 x ([Normal Albumin] - [Observed Albumin]) = 11 + 2.5 x (4.4 - 0.6) = 20.5 mEq/L. In this example, the albumin-corrected anion gap reveals the presence of a significant quantity of unmeasured anions. See also Osmol gap Delta ratio References External links Clinical Physiology of Acid-Base and Electrolyte Disorders Anion Gap Calculator (includes a correction for the albumin concentration) Metabolic acidosis by Merck More information about the Figge-Jabor-Kazda-Fencl equation Acid–base disturbances Electrolyte disturbances Medical mnemonics