Method and test strip for determining glucose in blood

• US 20040185517A1
• Filed: 01/29/2004
• Published: 09/23/2004
• Est. Priority Date: 02/04/2003
• Status: Active Grant

• Current Assignee: Ascensia Diabetes Care Holdings AG (PHC Holdings Corporation)
• Original Assignee: Bayer Healthcare LLC (Bayer AG)
• Inventors: Marfurt, Karen L.
• Granted Patent: US 7,439,033 B2
• Time in Patent Office: Days
• US Class Current: 435/14
• CPC Class Codes: A61B 2562/0295 Strip shaped analyte sensors for apparatus classified in A61B5/145 or A61B5/157
• 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: C12Q 1/54 involving glucose or galactose
• CPC Class Codes: C12Q 2326/00 Chromogens for determinations of oxidoreductase enzymes
• CPC Class Codes: G01N 33/66 involving blood sugars, e.g. galactose
• CPC Class Codes: Y10T 436/144444 Glucose

Abstract

A reagent strip for measuring the concentration of glucose in whole blood has a polymer on at least one side thereof to increase the opacity thereof, thereby reducing the effect of hematocrit on the glucose determination.

Claims

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

(a) providing a test strip having a sample side and a reaction side, the test strip being adapted to accept the sample on the sample side and pass it toward the reaction side, said test strip supporting a testing reagent, said testing reagent comprising a color indicator system that changes color to indicate the presence of glucose in the sample, said test strip further having a polymer on at least the reaction side, said polymer increasing the opacity of the reaction side of the test strip,

(b) applying the blood sample to the sample side of the test strip, and,

(c) measuring the change in color of the testing side to determine the glucose concentration in the blood.

2. The method of claim 1 wherein said polymer is selected form the group consisting of acrylic latex polymers, polystyrene sodium sulfate polymers, and combinations thereof.

3. The method of claim 1 wherein said porous membrane is made of a material selected from the group consisting of polyethersulfones and modified polyethersulfones.

4. The method of claim 1 wherein the testing reagent comprises a chemistry system selected from the group consisting of a PQQ-GDH system, a NAD-dependent GDH system, a hexokinase reductive system, and a glucose oxidase oxidative system.

5. The method of claim 1 wherein the indicator system is selected from the group consisting of tetrazolium compounds and tetrazolium salt compounds.

6. The method of claim 5 wherein the indicator system comprises a 2-thiazolyl tetrazolium salt compound.

7. The method of claim 1 wherein the reagent comprises a mediator compound selected from the group consisting of substituted or unsubstituted 3-phenylimino-3H-phenothiazines and 3-phenylimino-3H-phenoxazines.

8. The method of claim 1 wherein said test strip has pore sizes in the range of about 0.2 microns to about 5.0 microns.

9. The method of claim 8 wherein said test strip is isotropic.

10. The method of claim 8 wherein said test strip is anisotropic.

11. A test strip for measuring glucose concentration in a sample of whole blood that contains red blood cells, comprising

(a) a porous membrane having a sample side and a reaction side, the membrane being adapted to accept the sample on the sample side and pass it toward the reaction side,

(b) a testing reagent supported by the membrane, said testing reagent comprising a color indicator system that changes color to indicate the presence of glucose in the sample, and

(c) a polymer on at least the reaction side of the membrane, said polymer increasing the opacity of the reaction side of the membrane.

12. The test strip of claim 11 wherein said polymer is selected form the group consisting of acrylic latex polymers, polystyrene sodium sulfate polymers, and combinations thereof.

13. The test strip of claim 11 wherein said porous membrane is made of a material selected from the group consisting of polyethersulfones and modified polyethersulfones.

14. The test strip of claim 11 wherein the testing reagent comprises a chemistry system selected from the group consisting of a PQQ-GDH system, a NAD-dependent GDH system, a hexokinase reductive system, and a glucose oxidase oxidative system.

15. The test strip of claim 11 wherein the indicator system is selected from the group consisting of tetrazolium compounds and tetrazolium salt compounds.

16. The test strip of claim 15 wherein the indicator system comprises a 2-thiazolyl tetrazolium salt compound.

17. The test strip of claim 11 wherein the reagent comprises a mediator compound selected from the group of substituted or unsubstituted 3-phenylimino-3H-phenothiazines and 3-phenylimino-3H-phenoxazines.

18. The test strip of claim 11 wherein said test strip has pore sizes in the range of about 0.2 microns to about 5.0 microns.

19. The test strip of claim 18 wherein said test strip is isotropic.

20. The test strip of claim 18 wherein said test strip is anisotropic.