How a CGM works
A continuous glucose monitor (CGM) measures glucose with a thread-like filament that sits under the skin. Blood glucose is measured based on interstitial glucose - which is the fluid between skin cells.
The FreeStyle Libre CGM
Levels supports the FreeStyle Libre CGM which measures glucose levels every minute and stores readings in 15-minute intervals. The device is factory calibrated so that a blood sample is not needed. FreeStyle Libre sensors store the past eight hours of glucose information before and need to be scanned at least three times a day to prevent data loss.
Where can I get more information on the FreeStyle Libre?
You can read more information about the device here: