Systems and methods to compensate for sources of error during electrochemical testing

Patent metadata

Field	Value
Publication number	US-10359390-B2
Application number	US-201313920183-A
Country	US
Kind code	B2
Filing date	Jun 18, 2013
Priority date	Dec 22, 2010
Publication date	Jul 23, 2019
Grant date	Jul 23, 2019

Abstract

A method is disclosed for determining analyte concentration that includes applying a first electrical potential excitation pulse to a body fluid sample in an analyte sensor, and a first current response of the body fluid sample to the first pulse is measured. A second excitation pulse is applied to the body fluid sample in the analyte sensor, and a second current response of the body fluid sample to the second pulse is measured. An analyte level in the body fluid sample is determined by compensating for sources of error based on the first current response to the first pulse.

First claim

The invention claimed is:

1. A method for determining a concentration of an analyte in a body fluid sample using a reaction involving an enzyme and the analyte, comprising:
applying a first direct current (DC) pulse of electrical excitation to the body fluid sample in an analyte sensor, the analyte sensor including a first electrode, a second electrode and a reagent, the reagent covering the first electrode and the second electrode, the applying the first DC pulse step including having the first electrode act as a working electrode during the first DC pulse, the first DC pulse generating a first current response;
measuring the first current response at a plurality of times during the first DC pulse to obtain a first plurality of current measurements;
determining a reaction rate of the enzyme with the analyte based on the first plurality of current measurements;
applying a second DC pulse of electrical excitation to the body fluid sample, the applying the second DC pulse step including having the second electrode act as the working electrode during the second DC pulse, the second DC pulse generating a second current response;
measuring the second current response at a plurality of times during the second DC pulse to obtain a second plurality of current measurements; and
determining a concentration of the analyte in the body fluid sample based on the second plurality of current measurements compensated for the determined reaction rate.

2. The method of claim 1 , further comprising the step of applying a first open cell condition to the body fluid sample between the first and second DC pulses.

3. The method of claim 1 , wherein the determined concentration is compensated based on an algorithmic combination of the first and second pluralities of current measurements.

4. The method of claim 1 , wherein the first DC pulse has a first absolute voltage magnitude greater than a second absolute voltage magnitude of the second DC pulse to amplify effects of background current.

5. The method of claim 1 , wherein the applying the first DC pulse step comprises applying the first DC pulse for a first applying time based on the reaction rate detected from the first current response.

6. The method of claim 5 and further including determining the reaction rate, wherein the duration of the first applying time for the first DC pulse step is shortened or lengthened based on the reaction rate.

7. The method of claim 1 , further comprising the step of detecting fill sufficiency of the body fluid sample in the analyte sensor, wherein the applying the first DC pulse step occurs in response to detecting the fill sufficiency of the body fluid sample.

8. The method of claim 7 , further comprising the step of delaying the applying the first DC pulse step for an incubation time period after detecting the fill sufficiency of the body fluid sample.

9. The method of claim 1 , further comprising the steps of:
applying one or more pulses having an alternating current (AC) component to the body fluid sample in, the analyte sensor; and
measuring one or more AC responses to the pulses, wherein the determining the concentration of the analyte step includes compensating for interferents based on the one or more AC responses.

10. The method of claim 9 , wherein the applying the one or more AC pulses step occurs between the first DC pulse and the second DC pulse.

11. The method of claim 1 , wherein the determining the concentration of the analyte step compensates for variable reaction velocity of the enzyme.

12. The method of claim 1 , further comprising determining the reaction rate from a time-to-peak for the first current response based on the first plurality of current measurements.

13. The method of claim 1 , further comprising determining the reaction rate from the shape of the, first current response based on the first plurality of current measurements.

14. A method for determining a concentration of an analyte in a body fluid sample using a reaction involving an enzyme and the analyte, the method comprising measuring the current responses to first and second applied direct current (DC) pulses, comprising:
applying a first DC pulse of electrical excitation to the body fluid sample in an analyte sensor, the first DC pulse generating a first current response corresponding to the reaction of the enzyme with the analyte;
measuring the first current response during the first DC pulse to obtain a first current measurement;
determining a reaction rate for the reaction of the enzyme with the analyte using the first current measurement;
applying a second DC pulse of electrical excitation to the body fluid sample, the second DC pulse generating a second current response;
measuring the second current response during the second. DC pulse to obtain a second current measurement; and
determining a concentration of the analyte in the body fluid sample using the second current measurement, said determining including using an algorithm that varies, depending on reaction rate of the enzyme and the analyte, said determining further including adjusting the algorithm based on the determined reaction rate.

15. The method, of claim 14 in which the algorithm includes coefficients that vary depending on reaction rate, said determining including applying coefficients corresponding to the determined reaction rate.

16. The method of claim 14 , further comprising the step of applying a first open cell condition to the body fluid sample between the first and second DC pulses.

17. The method of claim 14 , wherein the determined concentration is compensated based on an algorithmic combination of the first and second pluralities of current measurements.

18. The method of claim 14 , wherein the first DC pulse has a first absolute voltage magnitude greater than a second absolute voltage magnitude of the second DC pulse to amplify effects of background current.

19. The method of claim 14 , wherein the applying the first DC pulse step comprises applying the first DC pulse for a first applying time based on the reaction rate detected from the first current response.

20. The method of claim 19 and further including determining the reaction rate, wherein the duration of the first applying time for the first DC pulse step is shortened or lengthened based on the reaction rate.

21. The method of claim 14 , further comprising the step of detecting fill sufficiency of the body fluid sample in the analyte sensor, wherein the applying the first DC pulse step occurs in response to detecting the fill sufficiency of the body fluid sample.

22. The method of claim 21 , further comprising the step of delaying the applying the first DC pulse step for an incubation time period after detecting the fill sufficiency of the body fluid sample.

23. The method of claim 14 , further comprising the steps of:
applying one or more pulses having an alternating current (AC) component to the body fluid sample in the analyte sensor; and
measuring one or more AC responses to the pulses, wherein the determining the concentration of the analyte step includes compensating for interferents based on the one or more AC responses.

24. The method of claim 23 , wherein the applying the one or more AC pulses step occurs between the first DC pulse and the second DC pulse.

25. The method of claim 14 , wherein the determining the concentration of the analyte step compensates for variable reaction velocity of the enzyme.

Assignees

• Roche Diabetes Care Inc

Inventors

• Burke David W
• Marquant Michael
• Surridge Nigel A

Classifications

• G01N27/3274 Primary

  Corrective measures, e.g. error detection, compensation for temperature or hematocrit, calibration (coding of calibration information G01N33/48771) · CPC title