Retrospective case reviews are a common method to identify potential adverse events. Because these reviews can be time-intensive, electronic trigger tools are frequently used to expedite screening. This study describes the use of an expedited review tool to detect possible, probable, and definite diagnostic errors in the emergency department. Errors were identified as “definite” or “probable” in 2.6% of cases and as “possible” in another 7%. Use of the trigger tool reduces the mean review time by nearly ten minutes.