New RFID Study Finds No Interference With Medical Devices

In the Dutch study, the initial distances during testing were 200 centimeters (6.6 feet) between an RFID system and a medical device, and moving the RFID system in increments of 50 centimeters (1.6 feet) both toward and away from the device, depending on whether EMI was recorded. The median distance for all EMI incidents was 30 centimeters in a range of 0.1 to 600 centimeters (0.04 inches to 19.7 feet).

Christe believes the non-clinical setting and the close proximity of the RFID systems to the medical devices is the reason the Dutch researchers recorded so many incidents of EMI. "I believe differences, at this point, will ultimately depend on your testing methods. What we did, which is so different [than the Dutch study], is we created a much more use-case scenario," she says, using an analogy to compare the Dutch study with hers: "Do people get hurt if they fall out of buildings? Yes, but that isn't the use case we studied. The use case we studied is people using stairs and elevators. That's the difference."

According to Christe, the Dutch study was designed to determine whether there was any EMI at all with regard to RFID systems, and was never intended to mimic a clinical study. "In the JAMA article, it says this was a controlled, non-clinical study," she says. The IUPUI study, on the other hand, was designed to look for EMI with RFID in a clinical setting. "Our assumption, rightly so, is that there certainly should not be an antenna within a foot of a medical device. That is not good practice; that is not how you should design a system. Our study wasn't intended to find out, Is there ever interference? We know—even BlueBean agrees—that yes, there is likely to be some interference with devices when RFID systems are not used as intended."

There may be some applications, Christe says, in which an antenna might be closer than 1 foot, but in these applications—such as an RFID-enabled wand used to detect tags sewn into surgical sponges that may have inadvertently been left inside a patient—the system's power would only be on for a short time, while the patient is scanned, and not continuously.

Researchers with the Dutch study could not be reached by press time.

Gregg Maggioli, president and CEO of BlueBean, and one of the study's authors, says he wanted to conduct the EMI study simply because he could not find any research studies examining EMI and RFID systems. "I worked quite a few weeks trying to find EMI studies," he states, "and the more research I did, and in talking with a number of people—I called the FDA [U.S. Food and Drug Administration] and several other places—everyone pretty much told me the same thing: that they hadn't seen issues with interference." The FDA has publicly stated, in fact, that it has not received any reports of injuries directly caused by EMI with medical devices. But while that was good news to hear, Maggioli says, "there still hadn't been any studies that I was aware of, so I figured we should do one."

BlueBean wants to extend its consulting and systems integration services to the health-care market, Maggioli says—specifically with passive UHF RFID systems for tracking assets and drug dispensing and administering. Therefore, he got together with Christe and others at IUPUI (BlueBean had worked on previous projects with the university), and they applied for and received a small grant from the Multidisciplinary Undergraduate Research Institute (MURI) program established by IUPUI’s School of Engineering and Technology.