System and methods to account for interferents in a glucose biosensor

• US 9,201,038 B2
• Filed: 07/24/2012
• Issued: 12/01/2015
• Est. Priority Date: 07/24/2012
• Status: Active Grant

• Current Assignee: Cilag Gmbh International (Johnson & Johnson)
• Original Assignee: LifeScan Scotland Limited (Johnson & Johnson)
• Inventors: Macfie, Gavin, Liu, Zuifang
• Primary Examiner(s): Ball, J. Christopher
• Application Number:
  US13/556,923
• Publication Number:
  US 20140027312A1
• Time in Patent Office: 1,225 Days
• Field of Search: 20440301-40315
• US Class Current: 1/1
• 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

Various embodiments that allow for improved accuracy in the measurement of glucose with a glucose meter and a biosensor, principally, by using pulsed signal inputs to the biosensor and selecting at least one specific pulsed output from the biosensor to determine a glucose concentration that is less affected by interfering chemical substances that might be present in the fluid sample.

Claims

1. An analyte measurement system comprising:

a biosensor having at least two electrodes with a reagent disposed proximate the at least two electrodes;

an analyte meter comprising;

a power supply;

memory for storage of data; and

a microprocessor coupled to the power supply and memory, and the biosensor, the microprocessor configured to determine an analyte concentration in a physiological sample by;

application of positive and negative electrical pulses to the at least two electrodes that repeat in sequence as a positive pulse, negative pulse, positive pulse and negative pulse, in which a voltage of at least one positive electrical pulse is at a generally constant magnitude during at least one discrete interval, followed by a voltage of at least one negative electrical pulse at a generally constant magnitude during at least one discrete interval;

obtain at least one current output over a predetermined time period from the at least two electrodes for each of the plurality of electrical pulses other than the first electrical pulse; and

calculate an analyte concentration based on the at least one current output.

3. The system of claim 1, in which the biosensor comprises a substrate on which the at least two electrodes are disposed, wherein the at least two electrodes comprise three electrodes, of which one of the three includes a reference electrode and two of the three are working electrodes.

4. The system of claim 1, in which the at least one current output comprises a negative current output of the last electrical pulse.

5. The system of claim 4, in which the microprocessor is configured to calculate the analyte concentration with an equation of the form:

11. The system of claim 5, in which the microprocessor is configured to calculate the analyte concentration with an equation of the form:

12. The system of claim 11, in which the analyte concentration comprises an average of the sum of the analyte concentrations G_p and G_N.

13. The system of claim 3, in which the sequence of pulses comprises a k number of pulses and the first current comprises an average of current outputs over the first predetermined time period within each pulse of the sequence of k pulses.

14. The system of claim 3, in which the sequence of pulses comprises a k number of pulses, and the first current comprises a summation of current outputs over the first predetermined time period within each pulse of the sequence of k pulses in which k comprises any whole number of at least 2.

15. The system of claim 3, in which the sequence of pulses comprises a k number of pulses, and the second current comprises an average of current outputs over the second predetermined time period within each pulse of the sequence of k pulses in which k comprises any whole number of at least 2.

16. The system of claim 3, in which the sequence of pulses comprises a k number of pulses, and the second current comprises a summation of current outputs over the second predetermined time period within each pulse of the sequence of k pulses in which k comprises any whole number of at least 2.

17. The system of claim 3, in which each of the first and second predetermined time periods comprises about the same duration of time.

18. The system of claim 3, in which the first predetermined time period comprises about 200 milliseconds and the second predetermined time period comprises about 200 milliseconds.

19. The system of claim 3, in which the magnitude of the positive electrical pulse comprises about 400 millivolts and the magnitude of the negative electrical pulse comprises about negative 400 millivolts.

20. The system of claim 3, in which the duration of the positive electrical pulse comprises about any duration from about 0.5 seconds to about 5 seconds.

21. The system of claim 3, in which the duration of the negative electrical pulse comprises about any duration from about 0.5 seconds to about 5 seconds.

2. An analyte measurement system comprising:

a biosensor having at least two electrodes with a reagent disposed proximate the at least two electrodes;

an analyte meter comprising;

a power supply;

memory for storage of data; and

a microprocessor coupled to the power supply and memory, and the biosensor, the microprocessor configured to determine an analyte concentration in a physiological sample by;

application of positive and negative electrical pulses to the at least two electrodes that repeat in sequence as a positive pulse, negative pulse, positive pulse and negative pulse, in which the sequence of electrical pulses is applied over discrete intervals and during each interval, a voltage of each of the positive electrical pulses is at a generally constant magnitude, and a voltage of at least one negative electrical pulse at a generally constant magnitude;

obtain at least a first current output from the from the at least two electrodes for each of a first predetermined time period due to application of at least one positive electrical pulse in the sequence other than the first electrical pulse;

obtain at least a second current output from the at least two electrodes for each of a second predetermined time period due to application of at least one negative electrical pulse in the sequence; and

calculate an analyte concentration based on at least one of the first and second current outputs.

6. The system of claim 2, in which the microprocessor is configured to calculate the analyte concentration with an equation of the form:

7. The system of claim 6, in which the sequence comprises a number of k pulses and each of the first output currents and second output currents comprises an output current measured at a predetermined time within each of the k number of pulses.

8. The system of claim 7, in which each of the first output currents comprises a summation of the positive output currents over a predetermined time duration during each pulse in the sequence of k pulses.

9. The system of claim 7, in which each of the second output currents a summation of the negative output currents over a predetermined time duration during each pulse in the sequence of k pulses.

10. The system of claim 9, in which the number k is at least 2.

22. A method to determine analyte concentration in a physiological sample with analyte meter having a microprocessor coupled to a power supply and memory and a biosensor having a reagent disposed on at least two electrodes, the method comprising:

depositing a physiological fluid sample on the reagent proximate the at least two electrodes of the biosensor;

applying a plurality of positive and negative electrical pulses to the at least two electrodes that repeat in sequence as a positive pulse, negative pulse, positive pulse and negative pulse with a positive electrical pulse being first in the sequence and at least one positive electrical pulse being next to the last pulse in the sequence, the applying step includes;

driving the plurality of positive electrical pulses of the sequence over discrete time intervals and during each interval, a voltage of each of the positive electrical pulses is at a generally constant magnitude, and

driving a plurality of negative electrical pulses of the sequence over at least one discrete time interval and during the at least one discrete interval, a voltage of the at least one negative electrical pulse is at a generally constant magnitude;

measuring a first current output over a first predetermined time duration from the at least two electrodes due to application of at least one positive electrical pulse in the sequence other than the first positive electrical pulse;

measuring a second current output over a second predetermined time period from the at least two electrodes due to application of at least one negative electrical pulse in the sequence;

determining a analyte concentration based on at least one of the first and second current outputs; and

annunciating the analyte concentration from the determining step.

23. The method of claim 22, in which the determining step comprises calculation of the analyte concentration with an equation of the form: