Wrenn used changes in the anion and bicarbonate gaps to gain insights into acid-base disorders. The author is from Strong Memorial Hospital in Rochester.


(1) delta anion gap (rise in anion gap from baseline)

(2) delta bicarbonate (fall in bicarbonate from baseline)


delta anion gap =

= (current anion gap) - (baseline anion gap)


delta bicarbonate gap =

= (baseline bicarbonate) - (current bicarbonate)


delta gap =

= (delta anion gap) - (delta bicarbonate)


Delta Gap


> 6

metabolic alkalosis

< -6

hyperchloremic acidosis


NOTE: The derivation of the anion gap includes serum bicarbonate.

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