ANALYTE SENSOR

• US 20130197333A1
• Filed: 06/28/2011
• Published: 08/01/2013
• Est. Priority Date: 06/30/2010
• Status: Abandoned Application

• Current Assignee: Edwards Lifesciences Corporation
• Original Assignee: Edwards Lifesciences Corporation
• Inventors: Petisce, James R.
• Application Number:
  US13/641,762
• Publication Number:
  US 20130197333A1
• Time in Patent Office: Days
• US Class Current: 600/347
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/14535 for measuring haematocrit
• CPC Class Codes: A61B 5/14539 for measuring pH
• 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 5/4839 combined with drug delivery
• CPC Class Codes: C12Q 1/003 Functionalisation
• CPC Class Codes: C12Q 1/006 for glucose
• CPC Class Codes: G01N 27/3274 Corrective measures, e.g. error detection, compensation for temperature or hematocrit, calibration coding of calibration information G01N33/48771

Abstract

The present disclosure relates generally to an electrochemical sensor comprising a membrane layer comprising one or both of an active enzymatic portion and an inactive-enzymatic or non-enzymatic portion, at least one electrode disposed beneath the membrane and either at least one pH sensor or a hematocrit sensor. The present disclosure also relates to methods of adjusting analyte concentration values using a correction factor based on measured pH values and/or measured hematocrit levels.

Claims

1. An analyte sensor comprising:

a membrane comprising an active enzymatic portion and an inactive-enzymatic or non-enzymatic portion;

at least two electrodes disposed beneath the membrane; and

at least one pH sensor disposed beneath the membrane and in proximity to the at least two electrodes.

2. The sensor of claim 1, wherein the at least one pH sensor is disposed beneath the membrane.

3. The sensor of any one of the previous claims, wherein the at least two electrodes comprises a working electrode and a blank electrode, and the membrane is partitioned over the working electrode and the blank electrode.

4. The sensor of claim 2, wherein the working electrode is disposed under the active enzymatic portion of the membrane and the blank electrode is disposed under the inactive-enzymatic or non-enzymatic portion of the membrane.

5. The sensor of claim 2, wherein the membrane is partitioned over the working electrode associated with the active enzymatic portion and the blank electrode associated with the inactive-enzymatic or non-enzymatic portion.

6. The sensor of claim 2, wherein the at least one pH sensor is positioned in closer proximity to the working electrode than the blank electrode.

7. The sensor of claim 2, wherein at least one pH sensor is positioned in closer proximity to the blank electrode than the working electrode.

8. The sensor of claim 2, wherein the at least one pH sensor is positioned at an equal distance from the working electrode and the blank electrode.

9. The sensor of claim 1, wherein the active enzymatic portion of the membrane comprises glucose oxidase.

10. The sensor of claim 2, wherein the working electrode and the at least one pH sensor is disposed on a first surface of a sensor substrate.

11. The sensor of claim 2, wherein the working electrode is disposed on a first surface of a sensor substrate, and the at least one pH sensor is disposed on a second surface of the sensor substrate.

12. The sensor of claim 1, wherein the membrane further comprises at least one of an electrode layer, an interferent layer, and a flux limiting layer.

13. The sensor of claim 1, wherein the at least one pH sensor is configured to determine a pH value of an environment in proximity to the at least two electrodes beneath the membrane.

14. A method comprising:

providing an analyte sensor adaptable to an infusion source, the sensor comprising;

a membrane layer comprising one or both of an active enzymatic portion and an inactive-enzymatic or non-enzymatic portion;

at least one working electrode disposed beneath one or both of the active enzymatic portion of the membrane and the inactive-enzymatic or non-enzymatic portion of the membrane; and

a pH sensor positioned in proximity to one or both of the at least one working electrode;

obtaining a first signal generated by the at least one electrode for determining a concentration of an analyte when in contact with an intravenous sample and providing an analyte concentration value based on the first signal;

obtaining a second signal generated by the pH sensor corresponding to a pH value beneath the membrane in proximity to the at least one working electrode;

providing a correction factor based on the second signal; and

adjusting the analyte concentration value using the correction factor.

15. The method of claim 14, wherein the analyte sensor is an intravenous blood glucose sensor (IVBG).

16. The method of claim 14, wherein the correction factor is determined using an algorithm.

17. The method of claim 14, wherein the algorithm comprises a pH correction curve.

18. The method any one of claims 14-17, wherein the second signal corresponds to one or more of the pH of the infusion source introduced to the analyte sensor or the pH of the intravenous sample.

19. The method of claim 18, wherein the pH of the infusion source differs from the pH of the intravenous sample.

20. The method any one of claims 14-17, further comprising obtaining a signal corresponding to a hematocrit level present in the bodily fluid and adjusting the calculated analyte concentration value based on the determined hematocrit level.

21. The method of claim 20 further comprising the steps of:

measuring an impedance value of the bodily fluid corresponding to a hematocrit level;

calculating a second correction factor based on the measured impedance value; and

adjusting the calculated analyte concentration value based on the calculated second correction factor.

22. The method of claim 21, wherein the calculated analyte concentration value is adjusted based on the calculated first correction factor and the calculated second correction factor.

23. The method of claim 14, wherein the pH sensor is disposed beneath the membrane.

24. The method of claim 14, wherein the pH sensor is disposed beneath an ion-sensitive membrane.

25. A system comprising:

an intravenous analyte sensor adapted for fluid communication with an infusion fluid source and intravenous fluids, the analyte sensor comprising;

at least one enzyme electrode configured to generate a first signal, corresponding to an analyte concentration value of the intravenous fluid; and

at least one pH sensor in proximity to the at least one enzyme electrode, the pH sensor configured to generate a second signal corresponding to a pH value of one or more of the infusion fluid source and the intravenous fluid; and

wherein the system is configured to adjust the analyte concentration value based on the pH value corresponding to the second signal.