System and method for determining the point of hydration and proper time to apply potential to a glucose sensor

• US 8,114,269 B2
• Filed: 12/28/2007
• Issued: 02/14/2012
• Est. Priority Date: 12/30/2005
• Status: Active Grant

• Current Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Inventors: Cooper, Kenneth W., Choy, David Y., Shah, Rajiv, Soundararajan, Gopikrishnan, Vejella, Ratnakar
• Primary Examiner(s): Olsen, Kaj K
• Assistant Examiner(s): Thai, Susan
• Application Number:
  US11/966,294
• Publication Number:
  US 20080156661A1
• Time in Patent Office: 1,509 Days
• Field of Search: 204400-435, 205775-7945, 435 4- 4052, 600309-367
• US Class Current: 205/792
• CPC Class Codes: A61B 17/3468 for implanting or removing devices, e.g. prostheses, implants, seeds, wires devices for implanting seeds A61M37/0069
• 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 5/6848 Needles
• CPC Class Codes: A61B 5/6849 in combination with a needle set
• CPC Class Codes: G01N 27/3271 Amperometric enzyme electrodes for analytes in body fluids, e.g. glucose in blood amperometry per se G01N27/49; aspects concerning the enzyme reagent C12Q1/001

Abstract

According to an embodiment of the invention, a method of determining hydration of a sensor having a plurality of electrodes is disclosed. In particular embodiments, the method couples a sensor electronics device to the sensor and measures the open circuit potential between at least two of the plurality of electrodes. Then, the open circuit potential measurement is compared to a predetermined value. In some embodiments, the plurality of electrodes includes a working electrode, a reference electrode, and a counter electrode. In still further embodiments, the open circuit potential between the working electrode and the reference electrode is measured. In other embodiments, the open circuit potential between the working electrode and the counter electrode is measured. In still other embodiments, the open circuit potential between the counter electrode and the reference electrode is measured.

Claims

1. A method of determining hydration of a sensor having a plurality of electrodes placed percutaneously or subcutaneously at a selected site in the body of a user, the method comprising the steps of:

coupling a sensor electronics device to the sensor;

measuring successive open circuit potential values between at least two of the plurality of electrodes;

calculating the rate of change of the measured open circuit potential values as the change over time between an open circuit potential value measured earlier in time and an open circuit potential value measured later in time;

comparing the open circuit potential values and the calculated rate of change to respective predetermined thresholds;

determining that the sensor is hydrated if said predetermined thresholds are met;

repeating, over a specified period of time, said measuring, calculating, and comparing steps if said predetermined thresholds are not met; and

if said predetermined thresholds are not met after the specified period of time has been exceeded, determining that the sensor will not hydrate and notifying the user to replace the sensor.

2. The method of claim 1, wherein the plurality of electrodes includes a working electrode, a reference electrode, and a counter electrode.

3. The method of claim 2, wherein the open circuit potential between the working electrode and the reference electrode is measured.

4. The method of claim 2, wherein the open circuit potential between the working electrode and the counter electrode is measured.

5. The method of claim 2, wherein the open circuit potential between the counter electrode and the reference electrode is measured.

6. The method of claim 2, wherein the open circuit potential between the working electrode and the reference electrode is measured, and wherein the open circuit potential between the working electrode and the counter electrode is measured.

7. The method of claim 2, wherein the open circuit potential between the working electrode and the reference electrode is measured, and wherein the open circuit potential between the counter electrode and the reference electrode is measured.

8. The method of claim 2, wherein the open circuit potential between the working electrode and the counter electrode is measured and wherein the open circuit potential between the counter electrode and the reference electrode is measured.

9. The method of claim 2, wherein the open circuit potential between the working electrode and the reference electrode is measured, and wherein the open circuit potential between the working electrode and the counter electrode is measured, and wherein the open circuit potential between the counter electrode and the reference electrode is measured.