Calibration techniques for a continuous analyte sensor

• US 8,386,004 B2
• Filed: 09/07/2011
• Issued: 02/26/2013
• Est. Priority Date: 12/05/2003
• Status: Active Grant

• Current Assignee: DexCom Incorporated
• Original Assignee: DexCom Incorporated
• Inventors: Kamath, Apurv Ullas, Simpson, Peter C., Brauker, James H., Goode, Paul V. Jr.
• Primary Examiner(s): Marmor, II, Charles A
• Assistant Examiner(s): D'ANGELO, MICHAEL J
• Application Number:
  US13/227,290
• Publication Number:
  US 20110319739A1
• Time in Patent Office: 538 Days
• Field of Search: 600/309, 600/316, 600345-347, 600/365, 435/4, 435/14, 436/68, 422/50, 422420-429, 20440301-40315, 702/23, 604 64- 66
• US Class Current: 600/347
• CPC Class Codes: A61B 2560/0223 of calibration, e.g. protocols for calibrating sensors
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/14865 invasive, e.g. introduced into the body by a catheter or needle or using implanted sensors
• CPC Class Codes: A61B 5/1495 Calibrating or testing of in-vivo probes
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: A61B 5/742 using visual displays A61B5/339 takes precedence
• CPC Class Codes: B33Y 80/00 Products made by additive manufacturing

Abstract

Disclosed herein are systems and methods for calibrating a continuous analyte sensor, such as a continuous glucose sensor. One such system utilizes one or more electrodes to measure an additional analyte. Such measurements may provide a baseline or sensitivity measurement for use in calibrating the sensor. Furthermore, baseline and/or sensitivity measurements may be used to trigger events such as digital filtering of data or suspending display of data.

Claims

1. A method for continuous glucose sensing, the method comprising:

generating a glucose signal associated with a glucose concentration in a host using a continuous glucose sensor;

measuring a sensitivity change of the continuous glucose sensor over a time period; and

determining, using electronic circuitry, a stability of the continuous glucose sensor based on the measured sensitivity change.

2. The method of claim 1, wherein the continuous glucose sensor comprises a membrane system, and wherein the measured sensitivity change is representative of a change in glucose transport through the membrane system.

3. The method of claim 1, wherein measuring the sensitivity change comprises measuring an analyte other than glucose.

4. The method of claim 1, wherein measuring the sensitivity change comprises measuring a change of oxygen transport through a membrane system of the continuous glucose sensor.

5. The method of claim 1, wherein the continuous glucose sensor comprises an electrode, and wherein measuring the sensitivity change comprises switching, cycling or pulsing a voltage applied to the electrode and evaluating a response to the applied voltage.

6. The method of claim 1, wherein measuring the sensitivity change comprises monitoring the glucose signal over a time period.

7. The method of claim 1, wherein measuring the sensitivity change is performed in vivo.

8. The method of claim 1, wherein the measured sensitivity change is not based on a reference glucose measurement from a reference glucose monitor.

9. The method of claim 1, wherein determining the stability further comprises detecting oxygen deprivation.

10. The method of claim 9, wherein detecting oxygen deprivation comprises examining the glucose signal for oxygen deprivation-induced artifacts.

11. The method of claim 1, further comprising calibrating the glucose signal using the measured sensitivity change.

12. The method of claim 1, further comprising controlling a display of the glucose signal responsive to the stability determination.

13. The method of claim 1, further comprising suspending display of the glucose signal responsive to the stability determination.

14. A system for continuous glucose sensing, the system comprising:

a continuous glucose sensor configured to generate a glucose signal associated with a glucose concentration in a host; and

electronic circuitry configured to determine a stability of the continuous glucose sensor by measuring a sensitivity change over a time period.

15. The system of claim 14, wherein the continuous glucose sensor comprises a membrane system, and wherein the measured sensitivity change is representative of a change in glucose transport through the membrane system.

16. The system of claim 14, wherein the continuous glucose sensor comprises an electrode, and wherein the electronic circuitry is configured to switch, cycle or pulse a voltage applied to the electrode.

17. The system of claim 16, wherein the electronic circuitry is configured to evaluate a response to the applied voltage.

18. The system of claim 14, wherein the electronic circuitry is configured to measure the sensitivity change without a reference glucose measurement from a reference glucose monitor.

19. The system of claim 14, wherein the electronic circuitry is further configured to determine the stability by detecting oxygen deprivation.

20. The system of claim 19, wherein the electronic circuitry is configured to detect oxygen deprivation by examining the glucose signal for oxygen deprivation-induced artifacts.

21. The system of claim 14, wherein the electronic circuitry is configured to calibrate the glucose signal using the measured sensitivity change.

22. The system of claim 14, wherein the electronic circuitry is configured to control a display of the glucose signal responsive to the stability determination.

23. The system of claim 14, wherein the electronic circuitry is configured to suspend display of the glucose signal responsive to the stability determination.

24. A system for continuous glucose sensing, the system comprising:

means for generating a glucose signal associated with a glucose concentration in a host using a continuous glucose sensor;

means for measuring a sensitivity change of the continuous glucose sensor over a time period; and

means for determining a stability of the continuous glucose sensor based on the measured sensitivity change.