Laboratory Protocol and Pilot Results for Dynamic Interference Testing of Continuous Glucose Monitoring Sensors

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Medical Devices

Background:

• Continuous glucose monitoring (CGM) sensors require stable fluidic environments for accurate performance.
• Previous in vitro interference testing used static concentrations, limiting real-world applicability.
• Dynamic testing is crucial to understand sensor behavior under fluctuating conditions.

Purpose of the Study:

• To develop and validate a novel macrofluidic test stand for dynamic in vitro interference testing of CGM sensors.
• To assess the impact of dynamic interferent concentrations on Dexcom G6 and Freestyle Libre 2 sensor performance.
• To establish a reliable protocol for evaluating CGM sensor accuracy against potential interfering substances.

Main Methods:

• A macrofluidic test stand utilizing HPLC pumps to generate programmable glucose and interferent gradients in PBS was designed.
• Experimental parameters including channel dimensions, flow rates, and gradient slopes were optimized.
• Dexcom G6 and Freestyle Libre 2 sensors were tested against dynamic gradients of maltose, acetaminophen, and xylose, with YSI 2300 Stat plus as the reference.

Main Results:

• Both CGM sensors accurately tracked programmed glucose changes.
• Dexcom G6 (G6) readings closely matched reference glucose levels post-calibration.
• Freestyle Libre 2 (L2) showed lower readings, potentially due to factory calibration; both sensors were affected by specific interferents (acetaminophen for G6, xylose for L2) and temperature.

Conclusions:

• The developed experimental setup and protocol offer a valuable method for dynamic in vitro testing of CGM sensors against interfering substances.
• This approach can contribute to improving the accuracy and reliability of future generations of continuous glucose monitoring sensors.
• Understanding dynamic interference is key to enhancing the clinical utility of CGM technology.