Continuous Glucose Monitor

A wearable sensor system that measures glucose levels in the fluid just beneath the skin at frequent, regular intervals and reports the trend to the wearer, rather than requiring a single fingerstick blood sample at one moment in time. A small filament or sensor is inserted just under the skin, usually on the arm or abdomen, and transmits readings wirelessly to a receiver, dedicated display, or smartphone application, often warning the user when a reading is rising or falling toward a dangerous level. Devices of this kind began reaching people with diabetes in the early 2000s and became markedly smaller, longer lasting, and more accurate over the following two decades, eventually needing little or no fingerstick calibration. Because the monitor shows the direction and speed of change as well as the current level, it is credited with helping many users, particularly those on insulin, catch and correct dangerous highs and lows earlier than intermittent testing would allow, and it is also the sensing half of automated insulin delivery systems that adjust an insulin pump's dosing in response to the readings.