The delta gap = ∆ anion gap/∆ bicarbonate. ∆ Anion gap = measured anion gap - 12 (12 is the normal anion gap) and ∆ bicarbonate = 24 - measured serum bicarbonate (24 is the normal serum bicarbonate level). The delta gap is measured in patients with high anion gap metabolic acidosis (HAGMA) to determine if a mixed acid-base disorder is present. If the delta ratio is 1–2, then only HAGMA is present. If the delta ratio is < 1, an additional normal anion gap metabolic acidosis is present. If the ratio is > 2.0, an additional metabolic alkalosis is present.