Determining Analyte Concentration From Variant Concentration Distribution In Measurable Species

• US 20150176054A1
• Filed: 03/10/2015
• Published: 06/25/2015
• Est. Priority Date: 10/24/2006
• Status: Active Grant

• Current Assignee: Ascensia Diabetes Care Holdings AG (PHC Holdings Corporation)
• Original Assignee: Bayer Healthcare LLC (Bayer AG)
• Inventors: Wu, Huan-Ping, Charlton, Steven C., Chu, Amy H., Edelbrock, Andrew J., Jung, Sung-Kwon, Huang, Dijia
• Granted Patent: US 10,190,150 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: A61B 5/1486 using enzyme electrodes, e.g. with immobilised oxidase
• CPC Class Codes: A61B 5/1495 Calibrating or testing of in-vivo probes
• CPC Class Codes: C12Q 1/004 mediator-assisted
• CPC Class Codes: C12Q 1/54 involving glucose or galactose
• CPC Class Codes: G01N 27/3271 Amperometric enzyme electrodes for analytes in body fluids, e.g. glucose in blood amperometry per se G01N27/49; aspects concerning the enzyme reagent C12Q1/001
• CPC Class Codes: G01N 27/3272 Test elements therefor, i.e. disposable laminated substrates with electrodes, reagent and channels optical biosensors G01N33/52

Abstract

A biosensor system determines an analyte concentration of a biological sample using an electrochemical process without Cottrell decay. The biosensor system generates an output signal having a transient decay, where the output signal is not inversely proportional to the square root of the time. The transient decay is greater or less than the −0.5 decay constant of a Cottrell decay. The transient decay may result from a relatively short incubation period, relatively small sample reservoir volumes, relatively small distances between electrode surfaces and the lid of the sensor strip, and/or relatively short excitations in relation to the average initial thickness of the reagent layer. The biosensor system determines the analyte concentration from the output signal having a transient decay.

Claims

1. A method for determining an analyte concentration in a sample, comprising:

forming a measurable species from reacting an analyte in the sample with an ionizing agent;

applying an input signal to the sample after an incubation period not exceeding 12 seconds, the input signal including an excitation and a relaxation;

responsive to applying the excitation, measuring an output signal while the measurable species reflects a variant concentration distribution; and

determining the analyte concentration of the sample based on the measured output signal.

2. The method of claim 1, wherein the variant concentration distribution represents an incomplete redox conversion of the analyte to the measurable species.

3. The method of claim 1, wherein the transient concentration distribution undergoes a substantial change from an electrode surface to an upper lid of a reservoir that is filled with the sample.

4. The method of claim 3, wherein a height of the reservoir is from 20 to 250 μ

m.

5. The method of claim 1, wherein the variant concentration distribution represents the measurable species undergoing a transient condition.

6. The method of claim 5, wherein the transient condition manifests as a transient decay of the output signal.

7. The method of claim 6, wherein the transient decay has a decay constant less than −

0.5 or greater than −

0.5.

8. The method of claim 7, wherein the transient decay is not inversely related to the square root of time.

9. The method of claim 7, wherein the decay constant is from 0.52 to 1 or at most −

0.35.

10. The method of claim 1, wherein the analyte concentration is determined before the analyte undergoes complete conversion to the measurable species.

11. The method of claim 1, wherein the input signal includes a plurality of excitations and a plurality of relaxations.

12. The method of claim 11, wherein at least one of the excitations has a duration from 0.1 to 5 seconds or from 0.1 to 1 second.

13. The method of claim 11, wherein at least one of the relaxations has a duration from 0.1 to 3 seconds.

14. The method of claim 1, wherein the input signal is a voltage and the output signal is a current.

15. The method of claim 1, wherein the incubation period does not exceed 8 seconds.

16. The method of claim 1, wherein the incubation period does not exceed 4 seconds.

17. The method of claim 1, wherein the incubation period does not exceed 1 second.

18. The method of claim 1, wherein the incubation period does not exceed 0.1 seconds.

19. A method for determining an analyte concentration in a sample, comprising:

forming a measurable species from reacting an analyte in the sample with an ionizing agent;

applying an input signal to the sample after an incubation period not exceeding 12 seconds, the input signal including an excitation and a relaxation;

responsive to applying the excitation, measuring an output signal while the measurable species undergoes a transient condition; and

determining the analyte concentration of the sample based on the measured output signal.

20. A method for determining an analyte concentration in a sample, comprising:

forming a measurable species from reacting an analyte in the sample with an ionizing agent;

applying an input signal to the sample after an incubation period not exceeding 12 seconds, the input signal including an excitation and a relaxation;

responsive to applying the excitation, measuring an output signal while the analyte undergoes incomplete redox conversion to the measurable species; and

determining the analyte concentration of the sample based on the measured output signal.