Objective Diagnostic errors in the emergency department (ED) are harmful and costly. We reviewed a selected high-risk cohort of patients presenting to the ED with abdominal pain to evaluate for possible diagnostic errors and associated process breakdowns.

Design We conducted a retrospective chart review of ED patients >18 years at an urban academic hospital. A computerised ‘trigger’ algorithm identified patients possibly at high risk for diagnostic errors to facilitate selective record reviews. The trigger determined patients to be at high risk because they: (1) presented to the ED with abdominal pain, and were discharged home and (2) had a return ED visit within 10 days that led to a hospitalisation. Diagnostic errors were defined as missed opportunities to make a correct or timely diagnosis based on the evidence available during the first ED visit, regardless of patient harm, and included errors that involved both ED and non-ED providers. Errors were determined by two independent record reviewers followed by team consensus in cases of disagreement.

Results Diagnostic errors occurred in 35 of 100 high-risk cases. Over two-thirds had breakdowns involving the patient–provider encounter (most commonly history-taking or ordering additional tests) and/or follow-up and tracking of diagnostic information (most commonly follow-up of abnormal test results). The most frequently missed diagnoses were gallbladder pathology (n=10) and urinary infections (n=5).

Conclusions Diagnostic process breakdowns in ED patients with abdominal pain most commonly involved history-taking, ordering insufficient tests in the patient–provider encounter and problems with follow-up of abnormal test results.