Determining Blood Glucose in a Small Volume Sample Receiving Cavity and in a Short Time Period

• US 20130284610A1
• Filed: 06/27/2013
• Published: 10/31/2013
• Est. Priority Date: 10/04/2002
• Status: Active Grant

• Current Assignee: Roche Diabetes Care Inc. (Roche Holding AG)
• Original Assignee: Roche Diagnostics Operations Incorporated (Roche Holding AG), Roche Operations Limited (Roche Holding AG)
• Inventors: Wilsey, Christopher D.
• Granted Patent: US 9,017,544 B2
• Time in Patent Office: Days
• US Class Current: 205/777.5
• CPC Class Codes: C12Q 1/006 for glucose
• CPC Class Codes: G01N 27/3272 Test elements therefor, i.e. disposable laminated substrates with electrodes, reagent and channels optical biosensors G01N33/52
• CPC Class Codes: G01N 27/3275 Sensing specific biomolecules, e.g. nucleic acid strands, based on an electrode surface reaction

Abstract

The concentration of glucose in a blood sample is determined by methods utilizing test strips having a sample receiving cavity having a volume of less than 1 μl and determining the glucose concentration within a time period of less than 10 seconds.

Claims

1. A method of determining the concentration of glucose in a blood sample, comprising:

providing a disposable, electrochemical biosensor test strip including a sample receiving cavity having a volume from 0.075 μ

l to less than 1 μ

l, and a reagent within the sample receiving cavity, the reagent including an enzyme and a mediator;

applying a blood sample containing glucose into the sample receiving cavity and into contact with the reagent to cause the blood sample to at least partially solubilize or hydrate the reagent, the glucose reacting with the reagent to produce an electroactive reaction product;

detecting the blood sample in the sample receiving cavity;

following said detecting, electrooxidizing the electroactive reaction product, said electrooxidizing producing an assay current;

within the time period from 3.5 seconds to less than 10 seconds after said detecting, measuring the assay current at one or more times and thereby obtaining one or more assay current measurements; and

within the time period from 3.5 seconds to less than 10 seconds after said detecting, determining the concentration of glucose in the blood sample using the one or more assay current measurements.

2. The method of claim 1 in which the mediator is readily-reversible.

3. The method of claim 1 in which said determining comprises determining the glucose concentration within the range of 50-600 mg of glucose/dL of blood and within the range of 20-70% Hct.

4. The method of claim 3 in which said determining comprises comparing the one or more measured currents to a current-to-concentration calibration to determine the glucose concentration.

5. The method of claim 1 in which said measuring and said determining are performed within the time period from 3.5 seconds to 6 seconds after said detecting.

6. The method of claim 5 in which said determining comprises determining the glucose concentration within the range of 50-600 mg of glucose/dL of blood and within the range of 20-70% Hct.

7. The method of claim 1 in which the sample receiving cavity has a volume from 0.075 μ

l to 0.775 μ

l.

8. The method of claim 7 in which said measuring and said determining are performed within the time period from 3.5 seconds to 6 seconds after said detecting.

9. The method of claim 7 in which the sample receiving cavity has a volume from 0.075 μ

l to 0.6 μ

l.

10. The method of claim 9 in which said determining comprises determining the glucose concentration within the range of 50-600 mg of glucose/dL of blood and within the range of 20-70% Hct.

11. The method of claim 9 in which said measuring and said determining are performed within the time period from 3.5 seconds to 6 seconds after said detecting.

12. The method of claim 11 in which said determining comprises determining the glucose concentration within the range of 50-600 mg of glucose/dL of blood and within the range of 20-70% Hct.

13. The method of claim 9 in which the sample receiving cavity has a volume from 0.25 μ

l to 0.6 μ

l.

14. The method of claim 13 in which said measuring and said determining are performed within the time period from 3.5 seconds to 6 seconds after said detecting.

15. The method of claim 14 in which said determining comprises determining the glucose concentration within the range of 50-600 mg of glucose/dL of blood and within the range of 20-70% Hct.

16. In an electrochemical method for determining the concentration of glucose in a blood sample, the method involving the use of a disposable, electrochemical biosensor test strip including a sample receiving cavity and a reagent within the sample receiving cavity, the reagent including an enzyme and a mediator, the method further utilizing a device configured to receive and operate the test strip, the method further involving applying a blood sample containing glucose into the sample receiving cavity and into contact with the reagent to cause the blood sample to at least partially solubilize or hydrate the reagent, the glucose reacting with the reagent to produce an electroactive reaction product, the improvement comprising:

the sample receiving cavity having a volume from 0.075 μ

l to less than 1 μ

l,

detecting the blood sample in the sample receiving cavity;

following said detecting, electrooxidizing the electroactive reaction product, said electrooxidizing producing an assay current;

within the time period from 3.5 seconds to less than 10 seconds after said detecting, measuring the assay current at one or more times and thereby obtaining one or more assay current measurements; and

within the time period from 3.5 seconds to less than 10 seconds after said detecting, determining the concentration of glucose in the blood sample using the one or more assay current measurements

17. The method of claim 16 in which the mediator is readily-reversible.

18. The method of claim 16 in which said determining comprises determining the glucose concentration within the range of 50-600 mg of glucose/dL of blood and within the range of 20-70% Hct.

19. The method of claim 18 in which said determining comprises comparing the one or more measured currents to a current-to-concentration calibration to determine the glucose concentration.

20. The method of claim 16 in which said measuring and said determining are performed within the time period from 3.5 seconds to 6 seconds after said detecting.

21. The method of claim 20 in which said determining comprises determining the glucose concentration within the range of 50-600 mg of glucose/dL of blood and within the range of 20-70% Hct.

22. The method of claim 16 in which the sample receiving cavity has a volume from 0.075 μ

l to 0.775 μ

l.

23. The method of claim 22 in which said measuring and said determining are performed within the time period from 3.5 seconds to 6 seconds after said detecting.

24. The method of claim 22 in which the sample receiving cavity has a volume from 0.075 μ

l to 0.6 μ

l.

25. The method of claim 24 in which said determining comprises determining the glucose concentration within the range of 50-600 mg of glucose/dL of blood and within the range of 20-70% Hct.

26. The method of claim 24 in which said measuring and said determining are performed within the time period from 3.5 seconds to 6 seconds after said detecting.

27. The method of claim 26 in which said determining comprises determining the glucose concentration within the range of 50-600 mg of glucose/dL of blood and within the range of 20-70% Hct.

28. The method of claim 24 in which the sample receiving cavity has a volume from 0.25 μ

l to 0.6 μ

l.

29. The method of claim 28 in which said measuring and said determining are performed within the time period from 3.5 seconds to 6 seconds after said detecting.

30. The method of claim 29 in which said determining comprises determining the glucose concentration within the range of 50-600 mg of glucose/dL of blood and within the range of 20-70% Hct.