isCGM

isCGM stands for intermittently scanned continuous glucose monitoring. It refers to glucose monitoring systems in which a sensor is worn on the body to measure interstitial glucose, but the data are primarily accessed only when the user scans the sensor with a reader or a compatible smartphone. Data are not continuously transmitted to a display, and glucose values, trend arrows, and historical data are retrieved at the moment of scanning.

In typical use, an isCGM sensor is worn for a defined period (often 10 to 14 days, depending on the device) and does not require fingerstick calibration in many cases. The user must scan the sensor to view the current glucose reading and the recent trend. Some models offer optional alert features, but the core characteristic of isCGM is that real-time data and alarms are not continuously presented unless a scan occurs. Data from scans can be uploaded to apps or cloud platforms for review by the user and health-care providers.

Compared with real-time CGMs (rtCGMs), isCGMs do not automatically push glucose data to a display or continuously monitor in the background. They can still support important diabetes-management metrics such as time in range, mean glucose, and glucose variability, derived from scanned data. Common examples of isCGM systems include the FreeStyle Libre family. IsCGMs emphasize user-initiated data retrieval and portability, with varying software options for data analysis and sharing.