TEMPERATURE COMPENSATION FOR ENZYME ELECTRODES

• US 20080125751A1
• Filed: 11/14/2007
• Published: 05/29/2008
• Est. Priority Date: 01/14/2002
• Status: Abandoned Application

• Current Assignee: Edwards Lifesciences Corporation
• Original Assignee: Edwards Lifesciences Corporation
• Inventors: Fjield, Todd, Curry, Kenneth, Higgins, Michael, Carlin, Patrick
• Application Number:
  US11/940,037
• Publication Number:
  US 20080125751A1
• Time in Patent Office: Days
• US Class Current: 604/523
• CPC Class Codes: C12Q 1/001 Enzyme electrodes
• CPC Class Codes: C12Q 1/006 for glucose
• CPC Class Codes: G01N 33/5302 Apparatus specially adapted for immunological test procedures

Abstract

A temperature compensation method for an enzyme electrode by measuring an operating temperature of the enzyme electrode, measuring the current generated by the enzyme electrode determining a deviation in measurement between the current generated and a reference current at the operating temperature, determining an enzyme concentration corresponding to the measured current, and calibrating the enzyme concentration to compensate for the deviation in measurement.

Claims

1. An apparatus for compensating for temperature comprising:

a catheter having a generally tubular body defining an opening and a lumen positioned adjacent to the opening;

a sensor positioned in the opening for producing a current; and

a temperature sensing device positioned in the lumen for determining a temperature of an area adjacent to the sensor and for compensating for an output of the sensor.

2. The apparatus of claim 1 wherein the catheter is selected from a group consisting of a glucose monitoring catheter and an intravascular catheter.

3. The apparatus of claim 1 wherein the sensor is selected from a group consisting of an enzyme electrode and a glucose electrode.

4. The apparatus of claim 1 further comprising a material used to hold the temperature sensing device in the lumen.

5. The apparatus of claim 1 wherein the temperature sensing device is a thermistor.

6. The apparatus of claim 1 further comprising a pathway positioned adjacent to the lumen for passing fluid.

7. The apparatus of claim 1 further comprising a membrane for containing the sensor.

8. The apparatus of claim 7 wherein the membrane is selected from a group consisting of a polyurethane membrane, a hydro-polymer membrane and a gel membrane.

9. A catheter for insertion into a body, the catheter comprising:

a sensor for generating a signal in response to an analyte concentration in the body; and

a temperature compensation element for determining a temperature of an area adjacent to the sensor and for compensating for an output of the sensor.

10. The catheter of claim 9 wherein the sensor is selected from a group consisting of an enzyme electrode and a glucose electrode.

11. The catheter of claim 9 wherein the temperature compensation element is a thermistor.

12. The catheter of claim 9 further comprising a membrane for containing the sensor.

13. The catheter of claim 12 wherein the membrane is selected from a group consisting of a polyurethane membrane, a hydro-polymer membrane and a gel membrane.

14. An apparatus for compensating for temperature comprising:

a generally tubular catheter body defining an opening;

a sensor positioned in the opening for producing a current in response to an analyte concentration; and

a temperature sensing device positioned adjacent to the sensor for determining a temperature of an area adjacent to the sensor and for compensating for an output of the sensor.

15. The apparatus of claim 14 wherein the sensor is selected from a group consisting of an enzyme electrode and a glucose electrode.

16. The apparatus of claim 14 further comprising a material used to hold the temperature sensing device in the opening.

17. The apparatus of claim 14 wherein the temperature sensing device is a thermistor.

18. The apparatus of claim 14 further comprising a pathway positioned adjacent to the temperature sensing device for passing fluid.

19. The apparatus of claim 14 further comprising a pathway positioned adjacent to the sensor for passing fluid.

20. The apparatus of claim 14 further comprising a membrane for coating the sensor.

21. The apparatus of claim 20 wherein the membrane is selected from a group consisting of a polyurethane membrane, a hydro-polymer membrane and a gel membrane.

22. A method for temperature compensation of an electrode comprising:

measuring a reference current;

measuring an electrode current received from the electrode;

determining a difference between the reference current and the electrode current;

determining an enzyme concentration corresponding to the electrode current; and

adjusting the enzyme concentration based on the difference between the reference current and the electrode current.

23. The method of claim 22 further comprising measuring an operating temperature of the electrode.

24. The method of claim 22 wherein the enzyme concentration is determined using the formula:

glucose concentration=slope·

current·

e<sup>Tcoeff(Tcal−

T)</sup>

where,

slope is a predetermined characteristic of the electrode;

current is the current generated by the electrode;

T_coeff is the temperature coefficient of the electrode;

T_cal is the temperature at which the electrode was calibrated; and

T is the operating temperature of the electrode.

25. A temperature compensation method for an enzyme electrode comprising:

measuring an operating temperature of the enzyme electrode;

measuring the current generated by the enzyme electrode;

determining a deviation in measurement between the measured current and a reference current at the operating temperature;

determining an enzyme concentration corresponding to the measured current; and

calibrating the enzyme concentration to compensate for the deviation in measurement using the relation;

glucose concentration=slope·

current·

e<sup>Tcoeff(Tcal−

T)</sup>

where,

slope is a predetermined characteristic of the enzyme electrode;

current is the current generated by the enzyme electrode;

T_coeff is the temperature coefficient of the enzyme electrode;

T_cal is the temperature at which the enzyme electrode was calibrated; and

T is the operating temperature of the enzyme electrode.