It is important to point out that the significant difference between glucose meters (GMs) or glucometers and continuous glucose monitors (CGMs) is that CGMs do not measure blood glucose levels. Whereas GMs or glucometers do measure blood glucose, CGMs instead measure glucose levels in interstitial fluid between layers of tissue. Although CGMs give a close estimation of blood glucose levels, there are physiological differences between the interstitial fluid and capillary blood, which may result in differences in glucose readings between the CGM systems and results from a fingerstick test using a GM or glucometer. Differences in glucose readings between interstitial fluid and capillary blood may be observed during times of rapid change in blood glucose, such as after eating, dosing insulin, or exercising.
