Sensor systems, devices, and methods for continuous glucose monitoring
Electrochemical impedance spectroscopy (EIS) may be used in conjunction with continuous glucose monitoring (CGM) to enable identification of valid and reliable sensor data, as well implementation of Smart Calibration algorithms.
1. A method for first day calibration (FDC) of a glucose sensor for measuring the level of glucose in a body of a user, said glucose sensor including physical sensor electronics, a microcontroller, and a working electrode, the method comprising:
(a) measuring, by said physical sensor electronics, the electrode current (Isig) for the working electrode;
(b) determining, by said microcontroller, if the glucose sensor is in a FDC mode of operation following a successful calibration of the glucose sensor;
(c) in response to the glucose sensor being in the FDC mode of operation following the successful calibration, determining, by said microcontroller, if the successful calibration was the first calibration of the glucose sensor following insertion of the glucose sensor into the body of the user;
(d) in response to the successful calibration of the glucose sensor being the first calibration of the glucose sensor, calculating, by said microcontroller, a calibration ratio (CR) based on said Isig;
(e) responsive to determining that the CR was calculated for the first calibration of the glucose sensor, comparing, by the microcontroller, said CR to a threshold range;
(f) in response to the CR being outside of the threshold range, setting, by the microcontroller, a next calibration of the glucose sensor to be performed at a first time interval, wherein performance of the next calibration of the glucose sensor performed at the first time interval is based on an electrochemical impedance spectroscopy (EIS) procedure performed via the physical sensor electronics; and
(g) in response to the CR being within the threshold range, setting by the microcontroller, the next calibration of the glucose sensor to be performed at a second time interval.
2. The method of claim 1 , wherein said threshold range is 4<CR<7.
3. The method of claim 1 , wherein the second time interval for the next calibration is 3 hours.
4. The method of claim 1 , wherein the first time interval for the next calibration is 6 hours.
5. The method of claim 1 , wherein the first time interval is greater than the second time interval.