Optimization of Reflex Testing Rules on the Sysmex XN ‐9100 Automated Hematology Line Improves Efficiency and Reduces Repeat Testing in Different Work Areas

INTRODUCTION: With the widespread implementation of automated hematology systems, Reflex testing plays a critical role in result verification. However, overly sensitive Reflex rules may lead to excessive repeat testing, increasing workload and prolonging sample turnaround time. This study optimized Reflex rules to improve workflow efficiency while maintaining analytical safety and accuracy. METHODS: A retrospective analysis was performed on 78,364 CBC results generated by the Sysmex XN-9100 hematology automation line in June 2025, including 43,758 outpatient and 34,606 emergency/ward samples. Reflex rules involving LW, PLT-F, WPC, and RET channels were optimized by differentiating initial and follow-up visit samples, introducing a 7-day historical result fluctuation safety range, and simplifying IP message combinations. Middleware simulation compared total Reflex rates and special-channel repeat counts before and after optimization. Existing autoverification logic, critical alert rules, manual review workflow, and high-risk disease-related repeat testing rules were retained. RESULTS: After optimization, total Reflex rates decreased significantly in both work areas (p < 0.01), from 16.03% to 14.36% in the outpatient area (relative reduction, 10.43%) and from 24.38% to 15.00% in the emergency/ward area (relative reduction, 38.47%). In the emergency/ward area, PLT-F, WPC, and RET repeat counts decreased by 44.86%, 49.19%, and 61.89%, respectively. CONCLUSION: XN automation line Reflex rule optimization reduced unnecessary repeat testing through initial/follow-up visit differentiation and historical fluctuation thresholds while retaining core risk-interception rules, supporting improved hematology workflow efficiency and reduced reagent consumption.