The primary goal of managing type 1 and type 2 diabetes has been to achieve closer-to-normal levels of blood glucose as much as possible. This goal has been helped by using home blood glucose monitoring devices several times daily. Blood glucose monitoring is critical to helping reduce hyperglycemia's occurrence and severity, and prevent short-term hypoglycemia complications.
Home glucose monitoring currently can be done using a glucose meter (GM) (also called a glucometer) or a continuous glucose monitor (CGM). The GM or glucometer typically uses a finger puncture to obtain a small droplet of blood placed on a reagent strip. Blood glucose reacts with the reagent strip to produce an electric current, which is measured by the glucometer and, in turn, calculates blood glucose level. Although glucometers measure blood glucose levels, one of the main disadvantages is the need to perform a finger puncture each time to determine blood glucose levels.
Continuous glucose monitors (CGMs) have gained popularity since their introduction in the late 1990s and early 2000s. They are widely used and accepted as a way to manage diabetes on a continuous and more frequent basis. The main advantages of a CGM device are the availability of constant daily glucose readings, audible alarms for high and/or low glucose levels, and the elimination or reduction in the use of finger sticks.
Unlike glucometers, CGMs do not measure blood glucose levels. Instead, they measure glucose levels in interstitial fluid between layers of tissue. The CGMs are calibrated to record a close estimate of blood glucose levels; however, there can be differences in glucose readings during rapid changes in blood glucose, such as after eating, dosing insulin, or exercising. This can affect the accuracy of the glucose reading using a CGM.
The two main types of CGM devices are real-time and intermittently scanned systems. Real-time CGMs have three main components: the sensor, the transmitter, the handheld receiver, and/or the smartphone app. The main advantage of the real-time CGM is the ability to have audible alarms for high or low glucose levels. Intermittently scanned CGMs require the user to monitor the device to obtain a glucose reading. Intermittently scanned CGMs have two main components: a combined glucose sensor/transmitter and a separate touchscreen reader.
