FDA Expands Indication for Dexcom G5 Continuous Glucose Monitoring System

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Dexcom G5 Transmitter -- Courtesy of Dexcom
Dexcom G5 Transmitter -- Courtesy of Dexcom

The US Food and Drug Administration (FDA) has expanded the indication for the Dexcom G5® Mobile Continuous Glucose Monitoring (CGM) System (Dexcom, Inc.) to allow for replacement of daily fingerstick blood glucose testing for diabetes treatment decisions in patients with diabetes aged 2 years or older, according to an agency press release.

This is the first CGM approved by the FDA that can be used to make treatment decisions without fingerstick capillary blood glucose confirmation, the FDA noted.

The device continuously measure and monitors interstitial glucose levels using a small sensor wire inserted below the skin and wirelessly sends real-time results every 5 minutes to a dedicated receiver and a compatible mobile device like a smartphone or tablet running a mobile app. Alarms and alerts signal whether glucose levels are above or below user-set thresholds.

The system must be calibrated at least twice a day using blood obtained from fingerstick tests, though additional daily fingersticks are generally no longer necessary. Unlike other CGM systems, results from the G5 Mobile CGM system can now be used directly by patients to make diabetes treatment decisions without confirmation from a traditional self-monitoring blood glucose meter.

The FDA based its decision on data from 2 clinical studies of the G5 Mobile CGM system that included 130 adults and children aged 2 years or older with diabetes. Both studies included a 7-day period during which the CGM system readings were compared with blood glucose meter values as well as a laboratory test method that measures serum glucose values. Patients reported no serious adverse events during the studies.

"The FDA works hard to help ensure that novel technologies, which can reduce the burden of daily disease management, are safe and accurate," Alberto Gutierrez, PhD, director of the Office of In Vitro Diagnostics and Radiological Health in the FDA's Center for Devices and Radiological Health, said in the release.

"Although this system still requires calibration with 2 daily fingersticks, it eliminates the need for any additional fingerstick blood glucose testing in order to make treatment decisions. This may allow some patients to manage their disease more comfortably and may encourage them to have routine dialogue with their health care providers about the use of real-time continuous glucose monitoring in diabetes management."

Risks associated with use of the CGM system include hypoglycemia or hyperglycemia in cases where information from the device is inaccurate and used to make treatment decisions or where hardware or set-up issues disable alarms and alerts. Skin irritation and redness from the device's adhesive patch may also be problematic.

Users are warned that the system must be calibrated using a fingerstick blood sample at least once every 12 hours and that taking any medications containing acetaminophen while wearing the system may falsely raise glucose readings.


  1. FDA expands indication for continuous glucose monitoring system, first to replace fingerstick testing for diabetes treatment decisions [news release]. Silver Spring, MD: FDA Newsroom; December 20, 2016. Accessed December 21, 2016.
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