A Continuous Glucose Monitor (CGM) is a compact device that provides continuous, twenty-four-hour tracking of glucose levels in the interstitial fluid (the fluid surrounding the cells). This system gives users a dynamic view of their glucose response to food, exercise, and medication, moving beyond the snapshot provided by a traditional fingerstick test. The accuracy of this constant data stream relies entirely on the small sensor inserted just beneath the skin. Understanding the required frequency and process for changing this sensor is fundamental to effective diabetes management.
Standard Sensor Lifespans and Replacement Schedules
The required frequency for changing a CGM sensor is determined entirely by the manufacturer, linked to regulatory approval for accuracy and safety over a specific timeframe. These fixed schedules ensure that the sensor’s enzymatic components, which measure glucose, do not degrade and compromise data reliability. Attempting to restart a sensor after its programmed lifespan has ended is not possible and can lead to inaccurate readings.
The most commonly used CGM systems have distinct lifespans that dictate the replacement cycle. For instance, Dexcom G6 and G7 sensors are designed to be worn for a maximum of 10 days before replacement is necessary. This period is followed by automatic deactivation and a prompt to insert a new sensor to maintain continuous monitoring.
In contrast, systems like the Abbott FreeStyle Libre 2 and 3 sensors are engineered for a longer duration, with a standard lifespan of 14 days. This 14-day window is clinically validated to maintain optimal accuracy, and the device is programmed to cease functioning once complete. Users must consult their specific device’s instructions to adhere to the proper replacement schedule.
Essential Preparation for Optimal Sensor Placement
Ensuring the new sensor lasts its full scheduled lifespan begins with meticulous preparation of the insertion site. Site rotation is important, as continuously using the same spot can lead to scar tissue formation, interfering with the sensor’s ability to accurately measure glucose. Users should select a new, recommended area for each replacement, allowing previous sites time to heal.
The chosen location must be flat, clean, and completely dry before the sensor is applied, which often involves scrubbing the area with an alcohol wipe. Let the skin air dry fully, as any remaining moisture or residue significantly impairs the adhesive’s secure bond. Users should also avoid applying lotions, creams, or oils near the site, as these compromise adhesion and sensor function.
Once the new sensor is inserted, gently applying firm pressure around the perimeter of the adhesive patch helps secure its placement. If premature dislodgement is frequent, users may benefit from supplementary adhesive products, such as skin barrier wipes or special over-patches. Proper initial adhesion prevents the sensor from lifting prematurely due to movement, sweat, or water exposure.
When to Remove a Sensor Before Its Scheduled Time
Although CGMs are designed to last their full duration, several common issues necessitate unscheduled removal and replacement. A primary reason is sensor malfunction, which presents as wildly inaccurate readings that do not align with physical symptoms or a confirmatory fingerstick blood glucose test. The device may also display specific error codes indicating an internal failure that prevents it from providing reliable data.
Physical issues with the sensor’s placement also require premature removal. This includes the sensor becoming partially or fully dislodged due to being snagged on clothing, bumped against a doorway, or having weakened adhesive. A sensor that has fallen off cannot be reinserted or reused; a new one must be applied immediately to restore glucose monitoring.
Furthermore, the sensor should be removed for safety if the user experiences severe or persistent skin irritation, an allergic reaction to the adhesive, or noticeable pain at the insertion site. If a sensor fails before its scheduled end date, users should document the issue and contact the manufacturer’s customer support line, as many companies offer a replacement.