Bluetooth Badges Slashed Hospital COVID Contact Tracing From 12 Hours to 10 Minutes

When a hospital worker tested positive for COVID-19 during the pandemic’s third wave, infection control teams at Yongin Severance Hospital in South Korea once faced a daunting ritual: hours of scrubbing through closed-circuit television footage, cross-checking visitor logs, interviewing colleagues, and reconstructing shifts from paper records. Every minute spent piecing together those movements was a minute the virus kept moving too. A new study published in BMC Health Services Research now quantifies just how much of that burden can be lifted by a technology that most people carry in their pockets without a second thought: low-energy Bluetooth.

Researchers led by Soon Sil Ko and Jin Young Park of the Center for Digital Health at Yongin Severance Hospital, part of Yonsei University College of Medicine, retrospectively analyzed nine confirmed COVID-19 cases among hospital staff and compared three tracing approaches: closed-circuit television alone, closed-circuit television combined with a real-time location system, and the location system on its own. The results were striking. Tracing that once took more than 12 hours of labor to identify 381 contacts was reduced to roughly 10 minutes for 918 contacts, a transformation the authors measured as a 99.8 percent reduction in the person-minutes required per identified contact.

The technology at the heart of the study is a Bluetooth Low Energy-based real-time location system, or RTLS. Unlike classic Bluetooth, which was designed for streaming audio and file transfers, Bluetooth Low Energy transmits small data packets in short bursts, allowing battery-powered tags to run for months or years on a single coin cell. In the hospital deployment, staff and admitted patients carried or wore small tags that periodically broadcast unique identifiers. Receivers distributed throughout the facility logged which tags passed within range of which access points, along with timestamps and signal-strength information. From those logs, the system could reconstruct who had been near whom, where, and when, without anyone needing to remember their own movements days later.

Signal strength is the crucial physical variable in such systems. Radio waves attenuate as they travel through air and are absorbed by walls, equipment, and human bodies, so the received signal strength indicator at a receiver provides a rough proxy for distance. By combining proximity thresholds with time windows, the RTLS could flag encounters likely to constitute meaningful exposure under epidemiological criteria, such as being within two meters of an infected person for more than a defined duration. This is precisely the kind of judgment that makes manual tracing so laborious: a contact tracer reviewing camera footage must visually estimate distance, track overlapping presence in a corridor or break room, and decide whether a fleeting pass-by counts as an exposure.

The implementation did not happen overnight. The researchers documented a phased rollout beginning in 2019, moving through initial deployment, institutional transition, and system enhancement. Early phases involved technical refinements to the tag network, expanded functionality, and, critically, work on compliance. A location system is only as good as its coverage of the people it is meant to track, and the team steadily improved adherence to BLE tag use among hospital staff until it reached 92.8 percent. Internal hospital documents and operational records were reviewed to identify the key technical and operational changes along the way, from upgrades to the web application server and database infrastructure to improvements in the graphical user interface that infection control staff used to query the system.

The headline numbers deserve unpacking. Before the RTLS was in place, tracing a single case using closed-circuit television alone required 770 minutes of work to yield 381 contacts, which works out to roughly 10.1 person-minutes per contact. After the system matured, the same task performed with RTLS data alone took about 10 minutes to enumerate 918 contacts, or approximately 0.02 person-minutes per contact. In other words, the system did not merely speed up the old process; it changed the economics of the task so dramatically that exhaustive tracing became feasible even when the number of potential contacts ballooned. During a fast-moving outbreak, that difference can determine whether quarantine decisions are made before or after secondary transmission occurs.

The efficiency gain also has a human dimension that the raw figures only hint at. Manual contact tracing in a hospital setting pulls skilled staff, often infection control nurses and epidemiologists, away from patient care for entire shifts. It exposes gaps in memory and gaps in camera coverage alike, and it can leave contacts unidentified until they themselves develop symptoms. A system that produces a contact list in minutes allows quarantine and testing decisions to be implemented the same day, shortens the window during which undetected carriers circulate through wards, and reduces the anxiety of staff who otherwise wait days to learn whether they were exposed. The authors frame this as a substantial improvement in in-hospital infection control capability, with the RTLS supporting rather than replacing clinical judgment.

The study is careful about its limits. It is a single-hospital case study conducted during one phase of one pandemic, and the comparison of CCTV-only, combined, and RTLS-only approaches is retrospective rather than a randomized trial. Accuracy in BLE proximity detection depends on receiver density, tag placement, and the radio environment of a building full of metal beds, imaging equipment, and moving bodies, all of which can scatter signals in ways that produce both false positives and false negatives. The authors also note that wider implementation raises questions of long-term economic sustainability, since maintaining thousands of tags, receivers, and servers carries recurring costs, and of ethics, because continuous location tracking of employees and patients sits uneasily beside privacy expectations even when data are anonymized and consented.

Those ethical questions were addressed explicitly in the study’s governance. Tags were assigned to admitted patients and relevant staff in accordance with institutional procedures, and written informed consent for routine RTLS monitoring included the potential use of anonymized RTLS-derived data for research purposes. The retrospective analysis itself was approved by the Institutional Review Board of Yongin Severance Hospital, which waived the requirement for individual informed consent given the study’s retrospective design, and the work was conducted in accordance with the Declaration of Helsinki. The research was supported by a grant from the Korea Health Technology R&D Project through the Korea Health Industry Development Institute, funded by the Ministry of Health and Welfare of the Republic of Korea, with the system’s installation and optimization supported by People and Technology Inc.

The broader significance of the findings extends well beyond one hospital’s pandemic response. Health systems worldwide invested heavily in digital tracing tools during COVID-19, from smartphone exposure-notification apps to wearable badges, with mixed and often debated results. This study offers one of the clearest quantitative demonstrations that, within the controlled environment of a single institution, a BLE-based location infrastructure can collapse the labor cost of contact tracing by three orders of magnitude. The authors point toward future studies evaluating long-term cost-effectiveness and the ethical architecture of wider deployment, questions that will matter as hospitals weigh whether the infrastructure built for pandemic emergencies should become permanent plumbing for infection control, outbreak investigation, and perhaps the everyday operational logistics of knowing where people and equipment are in a modern medical campus.

Subject of Research: Bluetooth Low Energy-based real-time location systems for hospital contact tracing during the COVID-19 pandemic

Article Title: Operational efficiency and practical utility of real-time location systems: a hospital-based case study during the COVID-19 outbreak

Article References: Ko, S. S., Ryu, U. H., Kim, S. J., Lee, J. H., Kim, K. D., Kim, N. Y., & Park, J. Y. (2026). Operational efficiency and practical utility of real-time location systems: a hospital-based case study during the COVID-19 outbreak. BMC Health Services Research. https://doi.org/10.1186/s12913-026-15775-6

Image Credits: AI Generated

DOI: 10.1186/s12913-026-15775-6

Keywords: real-time location systems, Bluetooth Low Energy, contact tracing, COVID-19, infection control, hospital informatics, health services research, Yongin Severance Hospital, digital health, wearable technology, operational efficiency, pandemic response