EP0110173A1
Expired / Lapsed
EP
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Test device and method for in a colored aqueous fluid by diffuse reflectance detecting a soluble analyte measurement
Assignee: LifeScan Inc
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Filing: 1983-10-31
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Granted: —
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Expires: 2003-10-31
Abstract
Abstract A test device of use in the diffuse reflectance colorimetric determination of analytes (e.g. glucose, ethanol) in coloured aqueous fluids (e.g. whole blood, blood serum, blood plasma) and its use in such determinations is disclosed. The test device comprises a diffuse reflective backing (12) to which is affixed a thin translucent hydrophilic substrate pad (11) (sample pad) which contains reagents (e.g. an oxydase for the analyte, a substance having peroxidase activity and a substance which will react with hydrogene peroxyde to give a coloured compound). The reagents react with the analyte being determined. The device finds preferred application in the measurement of sugars in fluids, especially glucose in whole blood. It requires only a small sample size and allows for simple and more accurate colorimetric determinations than before.
Inventors
- 👤 Roger C. Phillips
- 👤 Richard P. Thomson
- 👤 Raymond D. Underwood
- 👤 Geoffrey V. Mccarraugh
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-24 01:22
CPC Classifications
C; C12; C12Q; C12Q1/00; C12Q1/26; C12Q1/54; G; G01; G01N; G01N33/00; G01N33/48; G01N33/50; G01N33/52; G01N33/521; G01N33/523
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
92 words
Test device for detecting a soluble analyte, particularly glucose or ethanol, in a colored aqueous fluid, especially whole blood, blood serum and blood plasma, fruit based fluid or biological solution, by diffuse reflectance measurement, comprising a reagent containing flat sample pad on a backing characterized by a hydrophilic pad (11) containing the reagent which reacts with the analyte to yield a compound that absorbs at the wave length of measurement, said pad (11) being substantially translucent at the wave length of said measurement and being affixed to a diffuse reflective backing (12).
Claim 2
Dependent Claim
92 words
Test device for detecting a soluble analyte, particularly glucose or ethanol, in a colored aqueous fluid, especially whole blood, blood serum and blood plasma, fruit based fluid or biological solution, by diffuse reflectance measurement, comprising a reagent containing flat sample pad on a backing characterized by a hydrophilic pad (11) containing the reagent which reacts with the analyte to yield a compound that absorbs at the wave length of measurement, said pad (11) being substantially translucent at the wave length of said measurement and being affixed to a diffuse reflective backing (12).
Claim 3
Dependent Claim
35 words
Test device of claim 1 characterized in that the reagent comprises an oxidase for the analyte, a substance having peroxidase activity and a substance which will react with hydrogen peroxide to form a colored compound.
Claim 4
Dependent Claim
16 words
Test devide according to claim 1 or 2 characterized in that said pad (11) comprises cellulose.
Claim 5
Dependent Claim
20 words
Test device according to claim 3 characterized in that said pad (11) has a thickness of 0.03 to 0.4 mm.
Claim 6
Dependent Claim
28 words
Test device according to claim 3 for detecting glucose or ethanol of whole blood, characterized in that said pad (11) has a thickness of 0.05 to 0.3 mm.
Claim 7
Dependent Claim
103 words
Test device according to claim 4 for detecting glucose in whole blood characterized in that the hydrophilic cellulose pad (11) has a 10 to 50 mm 2 area through which at least about 35% of incident 600 nanometer or greater wavelength ligth can pass and is impregnated with a glucose oxidase, a substance having peroxidase activity and a substance which reacts with hydrogen peroxide to form a compound that absorbs in the 600 or greater nanometer range and in that the pad (11) is affixed to the diffuse reflective backing (12) such that at least about 35% of incident light is diffusely reflected.
Claim 8
Dependent Claim
109 words
Method for determining the concentration for an analyte, particularly glucose or ethanol, in a colored aqueous fluid, especially whole blood, blood serum, blood plasma, fruit based fluid or biological solution, which comprises bringing a sample of the fluid into contact with the sample pad of the test device according to any of claims 1 to 6 and performing a colorimetric determination, characterized by projecting a light beam of an appropriate wavelength through the sample pad and diffusely reflecting said beam off the reflective backing, observing by diffuse reflectance measurement the ligth intensity change at the wave- lenght of measurement, and relating the intensity change to the concentration of analyte.
Claim 9
Dependent Claim
78 words
Method according to claim 7 for determining the concentration of glucose in whole blood characterized by bringing a 5-20 microliter sample of whole blood in contact with the test pad of the test device of claim 6, projecting a 635 nanometer light beam through said pad and observing by diffuse reflectance measurement the intensity change of the beam diffusively reflected off of the diffusive backing at 635 nanometer and relating the intensity change to the concentration of glucose.
Claim 10
Dependent Claim
23 words
Method according to claim 7 or 8 characterized in that the intensity change is determined by comparing a blank with the test pad.
Claim 11
Dependent Claim
31 words
Method according to claim 7 or 8 characterized in that the intensity change is determined by comparing the intensity at two times after the sample is applied to the sample pad.
Claim 12
Dependent Claim
150 words
System for determining the concentration of glucose- containing whole blood comprising a test strip including a diffuse reflective backing (12) to which is affixed a sample pad (11) into which the whole blood is applied, said pad being flat, capable of transmitting 600 or greater nanometer wavelength light, consisting of hydrophilic cellulose, 0.03 to 0.40 mm thick and impregnated with an indicator comprising glucose oxidase, a peroxidase and a compound capable of generating color by reaction with hydrogen peroxide, means (15) for determining the generated color by diffuse reflectance measurements, means (20) for reading the diffuse reflectance measurement at at least two predetermined set time intervals after the whole blood has been applied into the sample pad (11), means (20, 21) for converting the difference in diffuse reflectance measurment so read into a concentration of glucose in the whole blood and means (22) for displaying the glucose concentration so obtained.
Claim 13
Dependent Claim
150 words
System for determining the concentration of glucose- containing whole blood comprising a test strip including a diffuse reflective backing (12) to which is affixed a sample pad (11) into which the whole blood is applied, said pad being flat, capable of transmitting 600 or greater nanometer wavelength light, consisting of hydrophilic cellulose, 0.03 to 0.40 mm thick and impregnated with an indicator comprising glucose oxidase, a peroxidase and a compound capable of generating color by reaction with hydrogen peroxide, means (15) for determining the generated color by diffuse reflectance measurements, means (20) for reading the diffuse reflectance measurement at at least two predetermined set time intervals after the whole blood has been applied into the sample pad (11), means (20, 21) for converting the difference in diffuse reflectance measurment so read into a concentration of glucose in the whole blood and means (22) for displaying the glucose concentration so obtained.
References Cited (Backward Citations)
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