The US Food and Drug Administration (FDA) has expanded the approved use of the G5 Mobile Continuous Glucose Monitoring System to replace fingerstick blood glucose testing in patients aged 2 years and older who have diabetes.

The system (Dexcom, Inc.) uses a small sensor wire inserted below the skin to continuously measure glucose levels. Results are sent wirelessly every 5 minutes to a dedicated receiver and to a mobile app on a compatible device, such as a smartphone or a tablet. In addition, alarms and alerts will indicate glucose levels above or below user-set thresholds.

The continuous glucose monitoring system must be calibrated at least 2 times per day using traditional fingerstick blood tests. However, the FDA notes that additional fingerstick tests throughout the day are no longer necessary, because the results of the device can be used directly by patients to make treatment decisions without confirmation from the fingerstick tests.

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The FDA used data from 130 adults and children 2 years of age and older with diabetes from 2 studies of the G5 Mobile Continuous Glucose Monitoring System. The studies included a 7-day period in which the system’s readings were compared with readings from a traditional blood glucose meter. The readings from the continuous glucose monitoring system were also compared with a laboratory test method that measures glucose values. No serious adverse events were reported during the studies.

The FDA notes some risks associated with the system, including hypoglycemia or hyperglycemia when information provided by the device is inaccurate and used to make treatment decisions, or when hardware issues disable alarms and alerts, and irritation or redness around the device’s adhesive patch. Users should be warned that the system must be calibrated every 12 hours with a fingerstick blood sample, and that taking medications containing acetaminophen when wearing the system could falsely raise glucose levels.

“Although this system requires calibration with 2 daily fingersticks, it eliminates the need for any additional fingerstick blood glucose testing in order to make treatment decisions,” stated Alberto Gutierrez, PhD, director of the Office of In-Vitro Diagnostics and Radiological Health in the FDA’s Center for Devices and Radiological Health.

“This may allow some patients to manage their disease more comfortably and may encourage them to have routine dialogue with their healthcare providers about the use of real-time continuous glucose monitoring in diabetes management.”


  1. US Food and Drug Administration. FDA expands indication for continuous glucose monitoring system, first to replace fingerstick testing for diabetes treatment decisions [press release]. Published December 20, 2016. Accessed January 3, 2017.