Comparison of Continuous Glucose Monitors.

Comparison of Continuous Glucose Monitors

The world of glucose monitoring is making an exciting shift from sole reliance on blood glucose meters to the increasing use of continuous glucose monitors. Continuous glucose monitors (CGM) provide glucose levels continuously (every 1 to 5 minutes) throughout the day by measuring glucose levels in the interstitial fluid (fluid between the body cells). Having such information allows the user to be proactive by seeing, in real-time, how food, exercise, and medicationimpact glucose levels.

Since their entry into the market place in 2000, continuous glucose monitors have continually been innovated resulting in improved accuracy, smaller sensors, and transmitters, and longer length of wear.1  In addition, insurance coverage for these devices continues to expand and improve making them more affordable. Research has shown that consistent use of CGM technology reduces hypoglycemia, lessens glycemic variability, and improves A1c.2

This article will compare many of the features available with the newest CGMs. For more background information on CGMs please refer to this article:

Medtronic Guardian Connect

Parts of the system: Guardian 3 sensor, Guardian 3 transmitter, Guardian connect app (displays sensor glucose data on smart phone), one-press serter - device used for placement of sensor

Sensor wear duration: 7 days

Sensor placement: Back of upper arm, abdomen (2 inches away from navel)

Warm-up time: Up to 2 hours

Alerts: Predictive alerts (notifies user of impending low glucose or high glucose) and threshold Alerts (notifies user of high glucose and low glucose)

Data Sharing: Yes, via a web-based app “care-partners” can receive text message alerts3

Accuracy: MARD (see below for definition): 8.7% when placed on the arm and calibrated 3-4 times/day and 9.6% when placed on abdomen and calibrated 3-4 times/day3

Dosing decisions: No. All dosing decisions require a blood glucose confirmation

Calibration (see below for definition): Every 12 hours3,4

Dexcom G 6

Parts of the system: Sensor, transmitter, display device (App on phone or Receiver), auto-applicator - device used for placement of sensor

Sensor wear duration: 10 days

Sensor placement: Abdomen (2 inches away from naval)

Warm-up time: 2 hours

Alerts: Urgent Low Soon Alert (20 minute warning prior to reaching or going below a glucose of 55 mg/dL) and threshold alerts (notifies user of high glucose and low glucose)

Data sharing: Yes, via the Dexcom Share App. Users can invite up to 5 people to followers to view real-time data and program text message alerts.

Accuracy: MARD: 9% 

Dosing decisions: Yes

Calibration: None required5

Freestyle Libre

Parts of the system: Sensor and reader, sensor applicator (device used for placement of sensor) and reader can also be used as a blood glucose monitor

Sensor wear duration: 10 days

Sensor placement: Back of upper arm

Warm-up time: 12 hours

Alerts: No alerts unless the sensor is scanned by Reader

Data sharing: No

Accuracy: MARD: 9.7 %6

Dosing Decisions: Yes

Calibration: None required


MARD: Mean Absolute Relative Difference is a statistical measure of accuracy; the lower the number, the better.5

Calibration: Blood glucose readings entered into the CGM system to help ensure the sensor glucose readings remain accurate over time.7

Do you currently use a continuous glucose monitor? Please share your experience with the community.

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This article represents the opinions, thoughts, and experiences of the author; none of this content has been paid for by any advertiser. The team does not recommend or endorse any products or treatments discussed herein. Learn more about how we maintain editorial integrity here.

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