Diagnostic error is an ongoing patient safety challenge, and can be exacerbated by the hectic pace of the emergency department (ED). This study assessed the feasibility of the Leveraging Patient’s Experience to Improve Diagnosis (LEAPED) program to measure patient-reported diagnostic error after ED discharge. Across three EDs, patient uptake of the program was high. Findings show that 23% of patients did not receive an explanation of their health problem upon discharge, and one-quarter of those patients did not understand the next steps after leaving the ED.