Continuous Glucose Monitor(CGM)
Definition
A wearable medical device that tracks glucose levels in interstitial fluid 24 hours a day through a tiny sensor inserted just under the skin. Most CGMs report readings every 1 to 5 minutes and transmit data wirelessly to a smartphone app or dedicated receiver. Devices like the Dexcom G7, Abbott FreeStyle Libre 3, and Senseonics Eversense E3 are the leading CGMs available in 2026.
Why “Continuous Glucose Monitor” Matters for Glucose Monitoring
Understanding continuous glucose monitor is essential for anyone using or evaluating a continuous glucose monitor. This concept directly affects how CGM devices are designed, how glucose data is interpreted, and how clinical decisions about blood sugar management are made. The technical foundations of CGM technology determine the accuracy, reliability, and user experience of every device on the market — from the Dexcom G7 to over-the-counter options like the Abbott Lingo.
This term is particularly relevant to 4 CGM products in our database. Understanding CGM helps you compare devices more effectively and choose the right continuous glucose monitor for your specific needs.
Related Terms
The fluid that surrounds cells in body tissue, where CGM sensors measure glucose concentration.
A CGM sensor technology that uses a glucose oxidase enzyme coating on a thin filament to generate an electrical current proportional to the glucose concentration in interstitial fluid.
The reusable electronic component that attaches to a CGM sensor and wirelessly sends glucose data to a smartphone, smartwatch, or dedicated receiver via Bluetooth.
A continuous glucose monitor that automatically and continuously transmits glucose readings to a display device — such as a smartphone, smartwatch, or insulin pump — without requiring the user to scan or interact with the sensor.
A type of glucose monitoring that stores continuous glucose data on the sensor but requires the user to scan the sensor with a smartphone or dedicated reader to view the current reading and recent trend data.
The required initialization period after inserting a new CGM sensor before it begins delivering glucose readings.