Background: Most emergency departments (ED) utilize medical directives to initiate lab investigations for patients prior to physician assessment. This practice facilitates expedited patient care in the ED, resulting in safer and efficient care. However, some patients choose to leave the ED prior to seeing a physician due to prolonged waiting. Previously, at our hospital there was no defined process for identifying and following up on abnormal test results on patients that leave without being seen (LWBS), resulting in lab results often not being reviewed by a nurse or physician. Aim Statement: By April 2020, we aim to have 90% of ED LWBS patients with abnormal results identified and followed up. Measures & Design: A series of consultations and information gathering occurred that included an environmental scan of other EDs and discussions with emergency nurses, emergency physicians, Risk Management, Legal Department, College of Nurses of Ontario and Canadian Medical Protective Association. A process map was developed collaboratively to standardize the process to identify and follow up on abnormal investigations of LWBS patients and a new hospital policy was developed to officially outline this process. The following are the family of measures: Outcome measure – % LWBS patients with abnormal tests that had follow-up documented in chart Process measure – Number LWBS patients with investigations initiated by medical directive, Number LWBS patients, % LWBS patients Balancing measure – Satisfaction of nurses with new process for LWBS patients Evaluation/Results: At baseline, 29% of LWBS patients with abnormal lab results had follow up documented in the chart. After implementation of the new standardized process and policy, the follow up rate of LWBS patients with abnormal results in August, September and October 2019 was 47%, 28% and 29% respectively. Discussion/Impact: These results indicate that standardization and new policy implementation is insufficient to change practice, even one that aims to provide safer patient care. Nevertheless, these interventions are important first steps to improving the safety for ED LWBS patients. We plan to implement an audit and feedback approach to encourage nursing staff to routinely check lab results on LWBS patients.