The difference between critical care initiation anion gap and prehospital admission anion gap is predictive of mortality in critical illness.

Objective: We hypothesized that the delta anion gap defined as difference between critical care initiation standard anion gap and prehospital admission standard anion gap is associated with all cause mortality in the critically ill.

Design: Observational cohort study.

Setting: Two hundred nine medical and surgical intensive care beds in two hospitals in Boston, MA.