Continuous glucose monitor

A continuous glucose monitor (CGM) is a device for monitoring <a href="/facts/Blood_glucose/I4SkNzrm">blood glucose</a> continuously instead of monitoring 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 <a href="/facts/Diabetes/2xeHXbsI">diabetes</a> with <a href="/facts/Insulin/oXG0myt1">insulin</a>, for example people with <a href="/facts/Type_1_diabetes/IkuQadGx">type 1 diabetes</a>, <a href="/facts/Type_2_diabetes/zCMXksmt">type 2 diabetes</a>, or other types of diabetes, such as <a href="/facts/Gestational_diabetes/1Nn5kF5G">gestational diabetes</a>.
A continuous glucose monitor has three parts:

<ul><li>a small <a href="/facts/Electrode/251PaKX8">electrode</a> that is placed under the skin</li>
<li>a transmitter that sends readings from the electrode to a receiver at regular intervals (every 1 to 15 minutes)</li>
<li>a separate receiver that shows the glucose level on a display.</li></ul>
Approved CGMs use an enzymatic technology which reacts with glucose molecules in the body's <a href="/facts/Interstitial_fluid/hzm4qatP">interstitial fluid</a> 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 that displays 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.

Continuous glucose monitor open-in-new

Continuous glucose monitor