[Requirements for continuous glucose monitoring]

Most people with type 1 diabetes rely on continuous glucose monitoring (CGM) for glucose control. However, the EU Medical Device Regulation (MDR) does not sufficiently ensure quality control due to lack of a standard for CGM devices. Several cases have been reported where healthcare providers had to discard CGM systems after purchase due to poor performance. Moreover, the mean absolute relative difference (MARD) is inadequate for measuring accuracy. MARD can be influenced by study design, e.g. by including individuals with type 2 diabetes, using only data during stable glucose levels, or assessing only the most accurate days of sensor survival. Instead, accuracy should be based on methods reflecting real-world challenges in people intended to use the device. Diagnosis, age and gender should be considered. The International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) is currently developing criteria for the evaluation of CGM systems.