How accurate is DexCom CGM in measuring glucose levels?

Asked 2 years ago
DexCom continuous glucose monitors, commonly referred to as CGMs, are known for their high level of accuracy in measuring glucose levels. The performance of these devices is rigorously tested and validated through clinical studies. Generally, DexCom CGMs, such as the DexCom G6 and G7 models, demonstrate a Mean Absolute Relative Difference, or MARD, of around 9 to 10 percent. This means that the readings provided by the devices are usually within about ten percent of the actual blood glucose levels. One important aspect of the accuracy of DexCom CGMs is their real-time monitoring capability, which allows users to receive continuous glucose data throughout the day and night. This feature helps individuals manage their diabetes more effectively by providing alerts for both high and low glucose levels. The algorithms used by DexCom utilize advanced technology that enhances the overall accuracy and reliability of the readings, even in situations where blood glucose levels fluctuate rapidly. It is worth noting that while the accuracy of DexCom CGMs is impressive, certain factors can affect measurement, such as hydration levels, movement, and sensor placement. Additionally, it is always recommended for users to perform blood glucose checks when making critical treatment decisions, such as administering insulin, especially if the CGM reading does not align with how the person feels. For the latest and more detailed information, including accuracy specifics for specific products, it is wise to refer to the current content on the DexCom website.
Adam Goldkamp is the editor / author responsible for this content.
Answered Jul 5, 2025

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