New RFID Study Finds No Interference With Medical Devices

Although the Dutch study revealed most incidents of EMI when the RFID systems were quite close to the medical devices, there were also some incidents that occurred at greater distances. In fact, out of a total of 123 testing attempts, three resulted in EMI in which the reader/tag and the medical device were as far apart as 600 centimeters (19.7 feet)—the maximum distance at which EMI was observed. What's more, a ventilator exhibited an EMI incident beginning at a distance of 400 centimeters (13.1 feet).

Christe says it is unclear why the Dutch study discovered incidents at such great distances, but adds that three incidents out of 123 testing attempts "is not a statistical sample that meets the bar as a validity. Perhaps they were anomalies?" The Dutch study, she notes, does not detail what was done when a device first experienced an EMI incident. If, for instance, there was an incident at 200 centimeters (6.6 feet), Christe wonders, did they simply persist in increasing the distance and continue to see such incidents?

"The thought is that if a device malfunctions, you need to bring in a new device, or reset the device somehow, and then test that, rather than continue to test an already malfunctioning device," Christe states. "So, it might be that the malfunction was induced, and the reader was moved further way, and 'yep, it was still malfunctioning.' You really want a functioning device at every test interval. If that isn't what they did, then that certainly might explain why they had those results—and if that isn't what they did, then I question their testing methods."

Both studies recommend further testing as necessary. The IUPUI-BlueBean study indicates that "this study determined that RFID systems, including near- and far-field antennas and passive tags, did not influence the performance of commonly used medical devices such as physiological monitors and intravenous pumps," but adds that "as new RFID components and systems are introduced, further study may be necessary to evaluate evolving RFID technology and its impact on medical equipment."

Christe calls Maggioli a "pioneer" in examining RFID systems and interference. "It was good that Gregg brought it up and stirred the pot to get our study going," she says. "But the question remains: How do you differentiate from real use case, as we feel we studied, and all the potential hazards that might exist with interference?"