US5620863A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Blood glucose strip having reduced side reactions
Assignee: LifeScan Inc
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Filing: 1995-06-07
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Granted: 1997-04-15
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Expires: 2015-06-07
Abstract
Abstract A reagent strip for measuring glucose concentration in a biological fluid containing red blood cells has reduced interference of hematocrit with the glucose measurement. When a biological fluid contacts the strip, it causes, in a reagent impregnated in the strip, a color change which is a measure of the glucose concentration in the fluid. However, the color change is also affected by the red blood cell concentration (hematocrit), thereby reducing the accuracy of the glucose measurement. The hematocrit effect is reduced by adding to the reagent a component, such as imidazole or imidazole and N-acetylglucosamine, for minimizing side reactions of the glucose, or its reaction products, with the fluid.
Inventors
- 👤 Michael F. Tomasco
- 👤 Maria Teodorczyk
- 👤 Remedios Dato
- 👤 Edward G. Rice
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 08:19
CPC Classifications
G; G01; G01N; G01N33/00; G01N33/48; G01N33/50; G01N33/66; C; C12; C12Q; C12Q1/00; C12Q1/54
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
150 words
A reagent strip for measuring glucose concentration in a biological fluid containing red blood cells, which comprises: a porous matrix having a sample side and a testing side, the matrix being adapted to accept a sample of the biological fluid on the sample side and pass the sample toward the testing side; and a testing reagent impregnated in the porous matrix, the testing reagent comprising a component for creating hydrogen peroxide from glucose and oxygen, a colored indicator for reacting with the hydrogen peroxide to cause a change in the color of the indicator, and, for minimizing side reactions of the glucose or the hydrogen peroxide with the biological fluid, a heavy metal-oxide-free solution of substituted imidazole of the general formula: ##STR3## where R 1 , R 2 , R 4 , and R 5 are independently either hydrogen or an alkyl group of from 1 to 3 carbons atoms.
Claim 2
Dependent Claim
150 words
A reagent strip for measuring glucose concentration in a biological fluid containing red blood cells, which comprises: a porous matrix having a sample side and a testing side, the matrix being adapted to accept a sample of the biological fluid on the sample side and pass the sample toward the testing side; and a testing reagent impregnated in the porous matrix, the testing reagent comprising a component for creating hydrogen peroxide from glucose and oxygen, a colored indicator for reacting with the hydrogen peroxide to cause a change in the color of the indicator, and, for minimizing side reactions of the glucose or the hydrogen peroxide with the biological fluid, a heavy metal-oxide-free solution of substituted imidazole of the general formula: ##STR3## where R 1 , R 2 , R 4 , and R 5 are independently either hydrogen or an alkyl group of from 1 to 3 carbons atoms.
Claim 3
Dependent Claim
20 words
The reagent strip of claim 1 wherein the component for creating hydrogen peroxide from glucose and oxygen comprises glucose oxidase.
Claim 4
Dependent Claim
88 words
The reagent strip of claim 1 wherein the indicator comprises a peroxidase and a material selected from the group consisting of (a) 3-methyl-2-benzothiazolinone hydrazone hydrochloride (MBTH) combined with 3-dimethylaminobenzoic acid (DMAB); (b) MBTH combined with 3,5-dichloro-2-hydroxybenzene-sulfonic acid (DCHBS); (c) 4-aminoantipyrene (4-AAP) and 5-oxo-1-(p-sulfophenyl)-2-pyrazoline-3-carboxylic acid (OPSP); (d) 4-AAP and N-(m-tolyl)-diethanolamine (NDA); (e) 2,2'-azino-di (3-ethylbenzthiazoline) sulfonic acid (ABTS); (f) 4-AAP and 4-methoxynaphthol; (g) pyrogallol red (PGR); (h) bromopyrogallol red (BPR); (i) Acid Green 25 (AG); or (j) [3-methyl-2-benzothiazolinone hydrazone] N-sulfonyl benzenesulfonate monosodium (MBTHSB), combined with 8-anilino-1-naphthalene sulfonic acid ammonium (ANS).
Claim 5
Dependent Claim
21 words
The reagent strip of claim 1 wherein the component for minimizing side reactions further comprises glucosamine of the general formula: ##STR4##
Claim 6
Dependent Claim
23 words
The reagent strip of claim 1 wherein the testing reagent further comprises an inhibitor to inhibit the change in color of the indicator.
Claim 7
Dependent Claim
14 words
The reagent strip of claim 1 wherein the matrix further comprises a separating component.
Claim 8
Dependent Claim
11 words
The reagent strip of claim 1 wherein the matrix is anisotropic.
Claim 9
Dependent Claim
12 words
The reagent strip of claim 1 wherein the biological fluid is blood.
Claim 10
Dependent Claim
22 words
The reagent strip of claim 1 wherein the testing reagent comprises glucose oxidase, a peroxidase, and a heavy metal-oxide-free solution of imidazole.
Claim 11
Dependent Claim
13 words
The reagent strip of claim 9 wherein the testing reagent further comprises N-acetylglucosamine.
Claim 12
Independent Claim
138 words
A method for measuring glucose concentration in a biological fluid containing red blood cells, which comprises the steps of: providing a porous matrix, which a) has a sample side and a testing side and b) is impregnated with a testing reagent that can react with glucose to cause a change in color of the testing side, the reagent comprising glucose oxidase, a peroxidase, an oxidizable dye or dye couple and a heavy metal-oxide-free solution of imidazole of the general formula: ##STR5## where R 1 , R 2 , R 4 , and R 5 are independently either hydrogen or an alkyl group of from 1 to 3 carbons atoms: applying the biological fluid to the sample side of the matrix; and measuring the change in color of the testing side to determine the glucose concentration in the fluid.
Claim 13
Independent Claim
138 words
A method for measuring glucose concentration in a biological fluid containing red blood cells, which comprises the steps of: providing a porous matrix, which a) has a sample side and a testing side and b) is impregnated with a testing reagent that can react with glucose to cause a change in color of the testing side, the reagent comprising glucose oxidase, a peroxidase, an oxidizable dye or dye couple and a heavy metal-oxide-free solution of imidazole of the general formula: ##STR5## where R 1 , R 2 , R 4 , and R 5 are independently either hydrogen or an alkyl group of from 1 to 3 carbons atoms: applying the biological fluid to the sample side of the matrix; and measuring the change in color of the testing side to determine the glucose concentration in the fluid.
Claim 14
Dependent Claim
24 words
The method of claim 11 wherein the glucose concentration in the biological fluid is in a range of about 40 to about 500 mg/dL.
Claim 15
Dependent Claim
25 words
The method of claim 11 wherein the biological fluid is blood which has a hematocrit level in a range of about 25% to about 60%.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-04-14 | 2000-10-14 | 2001-04-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-04-14 | 2004-10-14 | 2005-04-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-04-14 | 2008-10-14 | 2009-04-15 | $7700.00 | Window Closed / Lapsed |