Delta Gap

When evaluating a patient with an anion-gap acidosis, calculate a delta gap to check for there is a concomitant non-gap metabolic acidosis or metabolic alkalosis:
  1. Calculate the delta gap
    • Delta gap = patient’s anion gap – normal anion gap
  2. Add the delta gap to the patient’s bicarbonate
    • if it is < 24, suspect a concomitant non-gap metabolic acidosis
    • if it is > 30, suspect a concomitant metabolic alkalosis