Sensor systems, devices, and methods for continuous glucose monitoring

Patent metadata

Field	Value
Publication number	US-10327686-B2
Application number	US-201514980241-A
Country	US
Kind code	B2
Filing date	Dec 28, 2015
Priority date	Dec 28, 2015
Publication date	Jun 25, 2019
Grant date	Jun 25, 2019

Abstract

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.

First claim

What is claimed is:

1. A method for real-time calibration 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) performing, by said microcontroller, an electrochemical impedance spectroscopy (EIS) procedure to obtain imaginary impedance values for said working electrode;
(b) calculating, by said microcontroller, a reference range associated with said values of imaginary impedance, said range being a function of the difference between the current imaginary impedance value and prior imaginary impedance values, wherein said reference range is calculated according to the relation range=3×median(|x i −x j |), wherein j represents the current imaginary impedance value, and i represents the most recent 2 hours of imaginary impedance values;
(c) comparing, by the microcontroller, the current value of imaginary impedance to the reference range;
(d) based on said comparison, determining, by the microcontroller, a time interval until the next calibration; and
(e) setting, by the microcontroller, an alarm for performing said next calibration within said time interval based on said comparison.

2. The method of claim 1 , wherein said imaginary impedance values are filtered imaginary impedance values.

3. The method of claim 1 , wherein said imaginary impedance values are 1 kHz imaginary impedance values.

4. The method of claim 1 , wherein the reference range is clipped to be between 50Ω and 100Ω.

5. The method of claim 1 , wherein, said imaginary impedance values are filtered 1 kHz imaginary impedance values.

6. The method of claim 5 , wherein, if the current filtered 1 kHz imaginary value is outside of the reference range, the time interval until the next calibration is set at 6 hours from the most-recent calibration.

Assignees

• Medtronic Minimed Inc

Inventors

• Nogueira Keith
• Engel Taly G
• Li Xiaolong
• Liang Bradley C
• Shah Rajiv
• Kim Jaeho
• Liu Mike C
• Tsai Andy Y

Classifications

• A61B5/1473

  invasive, e.g. introduced into the body by a catheter · CPC title

• A61B5/14532 Primary

  for measuring glucose, e.g. by tissue impedance measurement · CPC title

• A61B5/0537

  Measuring body composition by impedance, e.g. tissue hydration or fat content · CPC title

• A61B5/742

  using visual displays (displays for heart-related electrical signals, e.g. ECG, A61B5/339) · CPC title

• A61B5/7225

  Details of analogue processing, e.g. isolation amplifier, gain or sensitivity adjustment, filtering, baseline or drift compensation (input circuits for detecting, measuring, or recording bioelectric or biomagnetic signals A61B5/30; specific diagnostic methods using bioelectric or biomagnetic signals A61B5/316) · CPC title