What do continuous glucose monitors measure?

Continuous glucose monitors (CGMs) measure interstitial glucose levels. These devices work by using a small sensor that is inserted under the skin, typically on the abdomen or arm. The sensor continuously measures the amount of glucose present in the interstitial fluid, which is the fluid that surrounds the body’s cells. This method provides real-time data on glucose levels, allowing individuals, particularly those with diabetes, to better manage their condition by understanding how their glucose levels fluctuate throughout the day and night.

The measurement of interstitial glucose is crucial because it reflects trends and changes in blood glucose levels, even though it is slightly delayed compared to blood glucose measurements from capillary or venous sources. This continuous monitoring is essential for making timely decisions about insulin usage, food intake, and activity levels, ultimately leading to improved diabetes management and enhanced quality of life.

In contrast, other options such as measuring venous blood glucose levels, fasting glucose, or capillary blood glucose pertain to traditional glucose monitoring methods rather than the continuous monitoring approach utilized by CGMs.