Real-world impact of implementing a 0/2-hour point-of-care high-sensitivity troponin pathway: interrupted time series and winter-matched difference-in-differences analysis

Background High-sensitivity cardiac troponin (hs-cTn) accelerated diagnostic pathways are central to acute coronary syndrome assessment. However, many centres continue laboratory-based strategies where turnaround time limits effective delivery of rapid rule-out algorithms. The system-level impact of implementing bedside point-of-care (POC) hs-cTn testing has not been robustly evaluated using time-series methodology. Purpose To evaluate the real-world operational impact of implementing a 0/2-hour POC hs-cTnI pathway in a high-volume tertiary emergency department (ED) using interrupted time series (ITS) and winter-matched difference-in-differences (DiD) analyses. Methods A hard-switch implementation of a bedside 0/2-hour high-sensitivity cardiac troponin I point-of-care pathway (i-STAT Alinity) replaced a laboratory-based 0/3-hour pathway (Alinity i). All adult (≥18 years) ED attendances undergoing troponin testing were included. Outcomes were emergency department length of stay (LOS) and 4-hour breach rate. A 75-day pre-implementation period was matched to a 75-day post-implementation period. Daily aggregated segmented regression was used to estimate immediate step and slope changes with Newey–West standard errors. Counterfactual modelling projected continuation of the laboratory 0/3-hour trajectory. Seasonal robustness was assessed using winter-matched DiD analysis. Results During the 75-day window, 2,769 troponin-tested attendances were analysed (mean 36.9/day). Baseline characteristics were comparable. Serial-testing patients demonstrated substantial raw improvement, with median LOS reducing from 466 to 417 minutes and 4-hour breach decreasing from 94.6% to 86.1%. ITS demonstrated significant immediate step reductions in median LOS overall (−65.4 minutes, 95% CI −123.0 to −7.8; p<0.05) and in serial patients (−147.7 minutes, 95% CI −233.5 to −62.0; p<0.001). Parallel reductions occurred in 4-hour breach rate (overall −11.7%; p=0.041; serial −15.2%; p<0.001). No significant slope change was detected, consistent with an immediate structural effect attributable to bedside availability of hs-cTn results following POC implementation. Counterfactual modelling estimated a mean post-implementation LOS gap of 82.3 minutes (95% CI 54.9 to 109.7) overall and 178.0 minutes (127.2 to 228.8) in serial patients. Conclusion Implementation of bedside point-of-care high-sensitivity troponin testing was associated with significant and sustained reductions in ED LOS and 4-hour breach rates, most pronounced among serial-testing patients. Time-series and winter-matched analyses indicate these improvements were not explained by seasonal variation. These findings support POC hs-cTn as a scalable operational intervention to unlock effectiveness of accelerated rule-out pathways in high-pressure emergency care systems.ITS Median Length of Stay OverallWinter Matched DiD for Serial Patients