A hair-thin filament with its coating, placed just under the skin
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Transmitter
Electronics that measure the sensor's current and send it wirelessly
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Display
A smartphone app or a dedicated receiver shows the value and trend
In Dexcom G7 the sensor and transmitter are combined into one small disposable.
PUTTING IT ON
A spring-loaded applicator
The user presses an applicator to the skin. A tiny introducer needle carries the filament just under the skin and then withdraws, leaving the filament in place. An adhesive patch holds everything on, and the whole process takes seconds.
The filament is placed once, and the needle does not stay in.
WEAR AND READINGS
How often, and for how long
ReadingsA new glucose value about every 5 minutes, roughly 288 a day
WearSensors last 10 days, and a newer G7 version lasts 15 days
Grace periodDexcom G7 adds a 12-hour grace period after the sensor session ends
CalibrationFactory calibrated, so no routine fingersticks are needed
A fresh sensor every 10 days is the routine, so the system makes this step quick.
ALERTS AND SHARING
The CGM watches so you don't have to
Urgent lowA fixed alert at 55 mg/dL that cannot be turned off
Low and highAlerts set by the user
Rate of changeAlerts when glucose is rising or falling fast
SharingReadings can be shared with family or caregivers
Insulin pumpsReadings can feed an automated insulin delivery system
Alerts are a large part of the value, especially overnight.
THE SIGNAL CHAIN
From skin to screen
Each stage turns a messy electrochemical signal into something a person can act on.
UNIT 10 STUDY COMPLETE
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Ready for the Fab Challenge?
You've covered the parts, wear, alerts, and signal path of a Dexcom CGM.