The Threshold of Serum Anion Gap as a Screening Tool for Organic Acidosis

Background: The serum anion gap (AG) is commonly used as a screening tool for acid-base disorders. With modern laboratory techniques using ion-selective electrodes to measure the main electrolyte components of the AG, our definition high AG (HAGMA) should be reviewed. Aim: This study aims to assess the diagnostic value of AG and to determine a diagnostic threshold for HAGMA in a high-prevalence clinical setting. Method: Computerized extraction of anonymised data from electronic medical records was performed. A pre-defined criteria included all inpatients of an acute-care hospital who had measurements for organic acids (lactate, ketone or salicylate) paired with a serum urea, electrolyte and creatinine panel.