Existing wireless medical telemetry systems
may be at increased risk of electromagnetic interference (EMI) if they continue
to operate in the range of frequencies in which most medical telemetry devices
are currently operating. To address this risk, the Federal Communications Commission
(FCC) has created a new Wireless Medical Telemetry Service (WMTS) that will
allow medical telemetry systems to operate on an interference-protected basis.
It is recommended that practioners evaluate whether their medical telemetry systems are at risk and take appropriate measures to reduce that risk. It is believed that the best way to accomplish this is to use telemetry systems operating in the new WMTS frequency bands.
Currently, most wireless medical telemetry devices operate as secondary users
in commercial broadcast TV bands and in the private land mobile radio service (PLMRS)
band. As secondary users, medical telemetry must accept interference from, and
not interfere with, primary licensed users. Typically, if there is interference
from a primary user, the medical telemetry system will be unusable. This
happened in 1998 when DTV transmissions disrupted medical telemetry systems in
two Texas hospitals. These frequency bands will be used more extensively by
digital TV and high power PLMRS operators, which is likely to result in an
increased risk of interference with medical telemetry. (For details of these
actions, see the Additional Detailed Information Section at the end of this
It is recommended that health care professionals determine whether their wireless medical telemetry
systems are at risk of EMI and to take appropriate action, if necessary,
to reduce that risk. Practioners may wish to consult with the
telemetry equipment manufacturer to discern the level of risk. This action should include, at a minimum,
determining at which frequencies particular telemetry systems are currently operating
(i.e., what frequency band, channel) and comparing that data with the
frequencies allocated to digital television (DTV) in the general area and the PLMRS
band. A list of all DTV allocations can be found on the FCC web
- If it is determined that
medical telemetry equipment is at risk of EMI from other in-band radio
frequency (RF) sources (e.g., DTV or PLMRS transmitters), the system should either be replaced with equipment that operates in the
WMTS bands (608-614 MHz, 1395-1400 MHz, and 1429-1432 MHz), when this
equipment is available, or modify it to operate in the WMTS band.
- If you and/or the telemetry equipment manufacturer determine that your
medical telemetry equipment is not at risk of EMI from other in-band RF
sources (e.g., DTV or PLMRS transmitters), then no change is necessary.
Risks should be assessed and necessary changes made to equipment as
soon as reasonable because licensed TV stations are authorized to begin testing
and transmitting in DTV channels as soon as they are ready, and because the FCC
will begin accepting applications for high-powered users in the 450-460 MHz band
January 29, 2001. Again, it is recommended by the FDA that medical telemetry
systems operate within the WMTS bands, particularly for new purchases, to
minimize the risk of EMI with wireless medical telemetry.
Reporting Adverse Events to FDA
The Safe Medical Devices Act of 1990 (SMDA) requires hospitals and other user
facilities to report deaths and serious illnesses and injuries associated with
the use of medical devices. This means that if interference with a medical
device results in a death or serious injury, you must report that event.
If a telemetry system fails to function due to electromagnetic interference
or any other reason, it is a device malfunction. Such malfunctions should be
reported to the manufacturer. Alternatively, they can be reported directly to
MedWatch, the FDA's voluntary reporting program. Submit reports to MedWatch by
telephone at 1-800-FDA-1088, by FAX at 1-800-FDA-0178, or by mail to MedWatch,
Food and Drug Administration, HF-2, 5600 Fishers Lane, Rockville, MD 20857.
Getting More Information
If you have any questions regarding this notice, please contact Nancy Pressly, FDA, CDRH, Office of Surveillance and
Biometrics, 1350 Piccard Drive, HFZ-510, Rockville, MD 20850, fax 301-594-2968,
or by e-mail at firstname.lastname@example.org.