Systems and methods for improving electrochemical analyte sensors

• US 20050161346A1
• Filed: 12/07/2004
• Published: 07/28/2005
• Est. Priority Date: 12/08/2003
• Status: Active Grant

• Current Assignee: DexCom Incorporated
• Original Assignee: DexCom Incorporated
• Inventors: Tapsak, Mark, Carr-Brendel, Victoria, Brauker, James, Goode, Paul, Simpson, Peter
• Granted Patent: US 7,081,195 B2
• Time in Patent Office: Days
• US Class Current: 205/792
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/1486 using enzyme electrodes, e.g. with immobilised oxidase
• 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: 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

An analyte-measuring device, particularly an electrochemical sensor, is provided for measuring current values at multiple bias potential settings to assess the quality of the analyte measurement, identify interference in the signal, and calculate substantially interference-free analyte concentration measurements. The device and method are suitable for calculating substantially interference-free analyte concentration measurements when glucose is the analyte and acetaminophen is an interfering species.

Claims

1. A method for identifying an interfering species using an analyte-measuring device, the method comprising:

providing at least one electrochemical sensor;

measuring a first signal output obtained at a first bias potential setting;

measuring a second signal output obtained at a second bias potential setting; and

comparing the first signal output with the second signal output to determine a differential measurement, thereby identifying a presence of an interfering species in a liquid.

2. The method of claim 1, wherein the interfering species is negatively identified when the differential measurement is below a set threshold.

3. The method of claim 1, wherein the interfering species is positively identified when the differential measurement is above a set threshold.

4. The method of claim 3, further comprising calculating an analyte concentration from the differential measurement, wherein the step of calculating is performed when interfering species are positively identified.

5. The method of claim 1, wherein the sensor is configured to switch between the first bias potential setting and the second bias potential setting.

6. The method of claim 1, wherein the step of providing comprises providing a first sensor at the first bias potential setting and a second sensor at the second bias potential setting.

7. The method of claim 1, wherein the interfering species is acetaminophen.

8. The method of claim 1, wherein the analyte measuring device is a glucose sensor.

9. The method of claim 1, wherein the liquid is a bodily fluid.

10. The method of claim 1, wherein the bodily fluid is interstitial fluid.

11. The method of claim 1, wherein the liquid is interstitial fluid, the analyte measuring device is a glucose sensor, and the interfering species is acetaminophen.

12. The method of claim 1, further comprising deriving an analyte concentration from the first signal output and the second signal output to determine an analyte concentration.

13. An analyte-measuring device for measuring a concentration of an analyte and identifying an interfering species, the device comprising at least one electrochemical sensor configured to provide a differential measurement of a current output signal at a first bias potential and at a second bias potential, wherein the differential measurement is employed to identify a species interfering with the analyte concentration.

14. The device of claim 13, wherein the electrochemical sensor is configured to switch between the first bias potential setting and the second bias potential setting.

15. The device of claim 13, further comprising a first sensor at the first bias potential setting and a second sensor at the second bias potential setting.

16. The device of claim 13, wherein the analyte comprises glucose and the interfering species comprises acetaminophen.

17. A method for identifying a signal interference in an analyte-measuring device, the method comprising:

providing at least one electrochemical sensor;

measuring a first signal output obtained at a first bias potential setting;

measuring a second signal output at a second bias potential setting;

comparing the first signal output with the second signal output to determine a differential measurement, thereby identifying an interference in the signal outputs.

18. The method of claim 17, further comprising deriving an analyte concentration from the first signal output and the second signal output to determine an analyte concentration.

19. The method of claim 17, further comprising measuring a third signal output at a third bias potential setting indicative of an additional interference in the signal outputs.

20. The method of claim 17, wherein the analyte comprises glucose and the interfering species comprises acetaminophen.