Question 1

What is the difference between the Dexcom G7 and the FreeStyle Libre 3?

Accepted Answer

The Dexcom G7 offers an 8.2% MARD, 10-day wear time, 30-minute warmup, and real-time customizable alerts with insulin pump compatibility. The FreeStyle Libre 3 has a slightly better 7.9% MARD, longer 14-day wear, 60-minute warmup, and real-time streaming but no pump integration. The G7 is preferred for type 1 diabetes and pump users; the Libre 3 is preferred for type 2 diabetes and cost-conscious users, as it is generally $50 to $100 cheaper per month.

Question 2

Which CGM has the longest sensor wear time?

Accepted Answer

The Eversense E3 implantable CGM lasts up to 365 days, far exceeding all disposable options. Among disposable sensors, the Dexcom Stelo leads at 15 days per sensor, followed by the FreeStyle Libre 3 and Libre 2 at 14 days, and the Dexcom G7 and G6 at 10 days. Longer wear time means fewer sensor changes, less adhesive irritation, and lower cost per day of monitoring.

Question 3

What is the difference between flash glucose monitoring and real-time CGM?

Accepted Answer

Flash glucose monitoring (also called intermittently scanned CGM) requires you to scan the sensor with your phone or reader to see your current glucose value — the original FreeStyle Libre and Libre 2 used this method. Real-time CGM automatically pushes glucose readings to your device every 1 to 5 minutes without scanning. The FreeStyle Libre 3, Dexcom G7, and Dexcom Stelo are all real-time CGMs. Real-time monitoring is essential for receiving automatic high and low glucose alerts.

Question 4

What is the difference between a prescription CGM and an OTC CGM?

Accepted Answer

Prescription CGMs (Dexcom G7, Dexcom G6, FreeStyle Libre 3, Eversense E3) are FDA-cleared for diabetes management, offer insulin dosing claims, and are covered by insurance. OTC CGMs (Dexcom Stelo, Abbott Libre Rio) are cleared for general glucose monitoring in adults 18+ who are not on insulin, do not require a prescription, and are not covered by insurance. OTC devices have slightly less stringent accuracy claims and lack insulin dosing indications but use the same core sensor technology.

Question 5

Should I choose an implantable CGM or a disposable one?

Accepted Answer

Implantable CGMs like the Eversense E3 are best for people who want long-term monitoring (up to 365 days) without the hassle of frequent sensor changes and adhesive wear. However, insertion and removal require a minor in-office procedure. Disposable CGMs (Dexcom G7, FreeStyle Libre 3) are self-applied at home in seconds, offer greater flexibility, and are covered by more insurance plans. Most users choose disposable CGMs; implantable devices represent less than 5% of the US CGM market.

Question 6

Which CGM is best for use with an insulin pump?

Accepted Answer

The Dexcom G7 is the most widely compatible CGM for insulin pump integration, working with the Omnipod 5 and Tandem t:slim X2 automated insulin delivery systems. The Dexcom G6 also integrates with these pumps. Medtronic's Guardian 4 sensor is designed exclusively for the MiniMed 780G pump system. Abbott's FreeStyle Libre line does not currently integrate with any insulin pump for automated insulin delivery, though this may change with future generations.

Real-Time CGM vs Flash Monitoring: Does the Difference Matter?

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