Continuous glucose monitor
A continuous glucose monitor (CGM) is a device used for monitoring blood glucose on a continual basis instead of monitoring glucose levels periodically by drawing a drop of blood from a finger. This is known as continuous glucose monitoring. CGMs are used by people who treat their diabetes with insulin, for example people with type 1 diabetes, type 2 diabetes, or other types of diabetes, such as gestational diabetes.
Abbott Laboratories' FreeStyle Libre CGM. The sensor and transmitter are fixed to the upper arm and the receiver shows current blood glucose level and a graph of recent blood glucose levels. | |
| Classification | Medical device |
|---|---|
| Uses | Blood glucose monitoring |
| Related | Fingerprick testing |
A continuous glucose monitor has three parts:
- a small electrode that is placed under the skin
- a transmitter that sends readings from the electrode to a receiver at regular intervals (every 1 to 15 minutes)
- a separate receiver that shows the glucose level on a display.
Currently approved CGMs use an enzymatic technology which reacts with glucose molecules in the body's interstitial fluid to generate an electric current that is proportional to glucose concentration. Data about glucose concentration is then relayed from a transmitter attached to the sensor to a receiver and display that shows the data to the user.
Some CGM devices must be calibrated periodically with traditional blood glucose measurements, but others do not require calibration by the user.