CGMs (Continuous Glucose Monitors) are devices that measure blood glucose on a continuous basis using a sensor device placed in the interstitial space using an enzymatic technology which reacts with glucose molecules, generating an electric current proportional to glucose concentration. Because it takes time for blood glucose to travel from the blood stream to the interstitial fluid, there is an inherent lag time of 5-20 minutes between actual blood glucose and the level measured by the CGM.

