Essential Safety Sheet in University Hospital and Healthcare Laboratories: A Comprehensive Evaluation Study with Longitudinal Impact Analysis

Background/Objectives: Safety information in hospital laboratories is often fragmented or difficult to retrieve under time pressure. We developed an Essential Safety Sheet (ESS) to present critical, task-level safety information immediately and evaluated its effectiveness on safety performance and incidents. Methods: We conducted a mixed-methods evaluation across eight university hospital laboratories from March 2023 to August 2024, including a 13-month interrupted time series with a concurrent difference-in-differences comparison between ESS and control laboratories (pre-implementation 6 months, implementation month, post-implementation 6 months). Primary outcomes were (1) emergency escalation accuracy, (2) information search time for task-critical items and (3) laboratory incident rates. Segmented regression models with robust Standard errors estimated level and slope changes; parallel trends were assessed pre-intervention. Multiple comparisons across the three primary outcomes were controlled for using the Bonferroni correction. Qualitative usability feedback was analyzed to contextualize the quantitative effects. Results: ESS implementation was associated with significant improvements in information search time and reductions in incident rates that were sustained over the post-implementation period in the ESS laboratories relative to the controls. Escalation accuracy improved in direction but did not reach statistical significance after multiple comparison correction (Bonferroni-adjusted p = 0.150). Findings were robust to the sensitivity analyses of model specification and pre-trend assumptions. Conclusions: A concise, task-level safety sheet can enhance the speed of safety-critical information retrieval and contribute to lower incident rates in hospital laboratories. While escalation accuracy showed only a favorable trend after correction, overall results support ESS as low-cost, scalable interventions to strengthen laboratory safety performance. Future studies should test generalizability across more sites and tasks to assess longer-term sustainability.