Harnessing a real-time location system for contact tracing in a busy emergency department

Abstract

With the persistent threat of emerging infectious diseases (EID), digital contact tracing (CT) tools can augment conventional CT for the prevention of healthcare-associated infectious disease transmissions. However, their performance has yet to be comprehensively evaluated in the fast-paced emergency department (ED). We compared the CT performance of the radiofrequency identification (RFID) based real time location system (RTLS) with conventional Electronic Medical Records (EMR review), against continuous direct observations of close contacts ("gold-standard") in a busy ED during pandemic period. The cross-sectional study was conducted at the ED in a large tertiary-care hospital in Singapore, from December-2020 to April-2021. We computed the CT performance (sensitivity, specificity, PPV, NPV, kappa) of RTLS, EMR and combination of the 2 approaches (Hybrid-CT), with respect to the direct observations. Finally, we calculated the Mean Absolute Error (MAE) between the duration of each contact episode found via RTLS and direct observations. Both RTLS and the hybrid-CT approach had the highest sensitivity of 0.955 (vs EMR 0.455) and highest NPV of 0.997 (vs EMR 0.968). RTLS also had the highest PPV of 0.777 (vs EMR 0.714; vs hybrid-CT 0.712). RTLS had the strongest agreement with the direct observation (kappa= 0.848). MAE between contact durations of 80 direct observations and their respective RTLS contact time was 1.81 minutes. RTLS was validated to be a high-performing CT tool, with significantly higher sensitivity than conventional CT via EMR review. RTLS can be used with confidence in time-strapped EDs for time-sensitive CT for the prevention of healthcare-associated transmission of EIDs.