Flash glucose monitoring versus oral glucose tolerance test: mind the gap

Wearable devices for continuous glucose monitoring (CGM) and flash glucose monitoring (FGM), also known as intermittent scanning continuous glucose monitoring (isCGM), have become largely available in high-income countries. However, glucose sensors are not intended for use in healthy subjects and no regulatory agency allows the prescription for either screening procedures or primary diagnosis of glycaemic metabolism disruption. As an example of the uncertainty, which can be fostered in unaware users, we here present a case of questionable impaired glucose tolerance assessed by means of both FGM and OGTT.