Reagent test strip for determination of blood glucose

• US 5,972,294 A
• Filed: 03/16/1998
• Issued: 10/26/1999
• Est. Priority Date: 04/04/1996
• Status: Expired due to Term

• Current Assignee: Lifescan Incorporated (Duv Holding Corporation)
• Original Assignee: Lifescan Incorporated (Duv Holding Corporation)
• Inventors: Smith, John L., Yu, Yeung
• Primary Examiner(s): ALEXANDER, LYLE
• Application Number:
  US09/039,577
• Time in Patent Office: 589 Days
• Field of Search: 422/56-58, 422/61, 436/95, 436/177
• US Class Current: 422/422
• CPC Class Codes: C12Q 1/54 involving glucose or galactose
• CPC Class Codes: G01N 33/66 involving blood sugars, e.g. galactose
• CPC Class Codes: Y10T 436/144444 Glucose
• CPC Class Codes: Y10T 436/25375 Liberation or purification of sample or separation of material from a sample [e.g., filtering, centrifuging, etc.]

Abstract

A reagent test strip is adapted for use in a blood glucose meter. A sample of whole blood is applied to one surface of a matrix on the strip and the meter measures the reflectance of the opposite surface of the matrix at about 635 nm and 700 nm and calculates from the reflectance the concentration of glucose in the sample. The portion of the applied sample that penetrates the matrix and is visible from the testing surface does not absorb light to any appreciable extent at 700 nm. Nevertheless, the glucose-containing sample interacts with the components of the reagent-containing matrix to cause a change in reflectance at 700 nm that simulates the effect of the blood color. As a result, the strip can be used in meters that measure glucose concentration in whole blood samples in the presence of optically visible hemoglobin.

Claims

1. A reagent test strip for use in an apparatus for determining a concentration of glucose in a sample of whole blood, the apparatus comprising optical means for detecting intensity of light at wavelengths of about 635 nm and about 700 nm reflected from at least a portion of a matrix disposed near one end of the strip, which matrix comprises

a) a sample receiving surface for receiving the whole blood sample and passing a portion of it toward a testing surface opposite thereto,

b) a structure that selectively retards the passage of red blood cells through the matrix, whereby any portion of the sample that is visible from the testing surface does not absorb light to any appreciable extent at about 700 nm, and

c) a reagent for indicating the glucose concentration by creating at the testing surface, about 15 seconds after the sample becomes visible there, a reduction in K/S at about 700 nm of at least about 0.2, thereby simulating the absorbance of hemoglobin in blood, and a reduction in reflectance at about 635 nm that is indicative of the glucose concentration, the reagent comprising a dye precursor selected from dyes and dye couples in the group consisting of bis[4-(N-alkyl-4-sulfopropyl)amino-2,6-dimethylphenyl]methane (BISMAP);

10-carboxymethylaminocarbonyl)-3,7-bis(dimethylamino) phenothiazine, sodium salt (leuco methylene blue);

4-aminoantipyrene (AAP) and N-ethyl-N-(3-sulfopropyl)-3,5-dimethylaniline, sodium salt (MAPS);

3-methyl-6-sulfonyl-2-benzothiazolinone hydrazone, sodium salt (SMBTH) and MAPS;

AAP and N-ethyl-N-(2-hydroxy-3-sulfopropyl)-3,5-dimethylaniline, sodium salt (MAOS); and

SMBTH and MAOS.

2. The strip of claim 1 in which the matrix comprises a membrane that has pores that trap the red blood cells of the whole blood sample.

3. The strip of claim 1 in which the matrix comprises a polysulfone membrane.

4. The strip of claim 1 in which the matrix comprises an anisotropic membrane.

5. The strip of claim 4 in which the membrane has pores that are larger near the sample receiving surface and smaller near the testing surface.

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

a) providing a reagent test strip that includes a matrix, which comprises:

i) a sample receiving surface for receiving the whole blood sample and passing a portion of it toward a testing surface opposite thereto,

ii) a structure that selectively retards the passage of red blood cells through the matrix, whereby any portion of the sample that is visible from the testing surface does not absorb light to any appreciable extent at about 700 nm, and

iii) a reagent for creating at the testing surface, about 15 seconds after the sample becomes visible there, a reduction in K/S at about 700 nm of at least about 0.2, thereby simulating the absorbance of hemoglobin in blood, and a change in reflectance at about 635 nm that is indicative of the glucose concentration;

b) inserting the strip into an apparatus for

i) removably locating the strip in a predetermined position,

ii) providing to the strip incident light at about 635 nm and about 700 nm when in the position, and

iii) determining the glucose concentration by measuring the intensity of light reflected from the testing surface of the matrix at about 635 nm and about 700 nm.

7. A reagent test strip for use in an apparatus for determining a concentration of glucose in a sample of whole blood, the apparatus comprising optical means for detecting intensity of light at wavelengths of about 635 nm and about 700 nm reflected from at least a portion of a matrix disposed near one end of the strip, which matrix comprises

a) a sample receiving surface for receiving the whole blood sample and passing a portion of it toward a testing surface opposite thereto,

b) a structure that selectively retards the passage of red blood cells through the matrix, whereby any portion of the sample that is visible from the testing surface does not absorb light to any appreciable extent at about 700 nm, and

c) a reagent for indicating the glucose concentration by creating at the testing surface, about 15 seconds after the sample becomes visible there, a reduction in K/S at about 700 nm of at least about 0.2, thereby simulating the absorbance of hemoglobin in blood, and a reduction in reflectance at about 635 nm that is indicative of the glucose concentration, the reagent comprising

(i) a first dye precursor selected from a dye and dye couples in the group consisting of BISMAP;

3-methyl-2-benzothiazolinone hydrazone hydrochloride (MBTH) and N-ethyl-N-(3-sulfopropyl)aniline, sodium salt (ALPS);

SMBTH and ALPS;

AAP and N-ethyl-N-(3sulfopropyl)-3,5-dimethoxyaniline, sodium salt (DAOS); and

(ii) a second dye precursor selected from dyes and dye couples in the group consisting of leuco methylene blue;

N-carboxylmethylaminocarbonyl)-4,4'"'"'-bis(dimethylamino)diphenylamine, sodium salt (leuco Bindschedler'"'"'s green);

N-methyl-N-phenyl-1,4-benzenediamine (NCP-04) and ALPS;

N-methyl-N-(3-methylphenyl)-1,4-benzenediamine (NCP-05) and DAPS; and

N-methyl-N-(3-methoxylphenyl)-1,4-benzenediamine (NCP-06) and N-ethyl-N-(2-hydroxy-3-sulfopropyl)-3-methoxyaniline, sodium salt (ADOS).

8. The strip of claim 7, in which the first and second dye precursor each include a composition selected from the group consisting of ALPS, DAPS, and DAOS.