Visual blood glucose concentration test strip

• US 5,306,623 A
• Filed: 07/26/1991
• Issued: 04/26/1994
• Est. Priority Date: 08/28/1989
• Status: Expired due to Term

• Current Assignee: Lifescan Incorporated (Duv Holding Corporation)
• Original Assignee: Lifescan Incorporated (Duv Holding Corporation)
• Inventors: Tomasco, Michael F., Kiser, Ernest J., Rice, Edward G.
• Primary Examiner(s): Wityshyn, Michael G.
• Assistant Examiner(s): GITOMER, RALPH J
• Application Number:
  US07/736,537
• Time in Patent Office: 1,005 Days
• Field of Search: 422/56, 422/57, 422/101, 435/4, 435/14, 435/25, 435/28, 436/177
• US Class Current: 435/14
• CPC Class Codes: C12Q 1/54 involving glucose or galactose
• CPC Class Codes: G01N 33/48 Biological material, e.g. blood, urine G01N33/02, G01N33/26, G01N33/44, G01N33/46 take precedence; Haemocytometers counting blood corpuscules distributed over a surface by scanning the surface G06M11/02
• CPC Class Codes: G01N 33/521 Single-layer analytical elements
• CPC Class Codes: G01N 33/523 the element being adapted for a specific analyte
• 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 separation matrix impregnated with a separating agent separates red blood cells or hemoglobin from whole blood. Upon separation, an impregnated test reagent reacts with the separated substantially clear component fluid to form a colored product which enables a visual or meter test for analyte levels in whole blood. Such a test is appropriate for, among other things measuring glucose, cholesterol, or alcohol levels in whole blood samples. A visual meter is disclosed which allows sample to be applied to one side of the strip, and reading takes place on the opposite side, after separation of red blood cells and reaction to test reagent. Also, a useful test strip format is disclosed.

Claims

1. A reagent strip comprising:

a porous matrix having sample side and a test side, said matrix uniformly impregnated with a separation coating and a testing reagent;

an upper support member upon which the matrix is mounted, having a slit which extend through the upper support member and permits visual observation of the test side;

a lower support member having a hole therethrough, said lower support member and said upper support member substantially surrounding the matrix;

said lower support member and said matrix defining a capillary gap therebetween which communicates with the hole and with a portion of the sample side opposite the slit;

said matrix having a pore size distribution suited to accept a whole blood sample suspected of containing glucose as an analyte applied onto said sample side via the hole and to pass said sample toward said test side by capillary actions;

said separation coating capable of separating from said whole blood a substantially clear component fluid containing said glucose by selectively retarding the passage of red blood cells through the matrix;

said testing reagent comprising an enzyme, a dye indicator, and a dye inhibitor capable of reacting with said glucose in said clear component fluid to vary coloration of the test side of said matrix, dependent upon the concentration level of the glucose in said fluid;

wherein said separation coating is selected from the group consisting of polyvinyl sulfonic acid, polyethylene glycol, polystyrene sulfonic acid, hydroxypropyl cellulose, polyproplene glycol, polyvinyl pyrrolidone and polyacrylic acid; and

said indicator and said inhibitor are present together on said matrix in bands, such that each band corresponds to one of two or more predetermined glucose concentrations and the presence of glucose concentrations in said whole blood sample which are equal to or greater than said predetermined concentrations may be detected by inspecting each band on the test side though said slit for variations in coloration.

2. The reagent strip of claim 1 wherein said testing reagent comprises glucose oxidase, horseradish peroxidase and an indicator selected from the group consisting of alizarin cyanin green, bromopyrolgallol red, anazolene sodium, pyrogallol- sulphophthalein, 2,2'"'"' azino-di-[3]ethylbenzthiazoline sulfonate.

3. The reagent strip of claim 1 further comprising a buffer selected from the group consisting of aconitic acid, malic acid, citric acid, and fumaric acid.

4. The reagent strip of claim 1 further comprising ethylene diamine tetraacetic acid as a chelator and an inhibitor selected from the group consisting of propyl gallate, ascorbic acid, gallic acid, isoascorbic acid, 3,4 dihydroxy cinnamic acid, 3,4 dihydroxybenzaldehyde, and 5,6-diaminouracil.

5. A reagent strip comprising:

a porous matrix having a sample side and a test side, said matrix uniformly impregnated with a separation coating and a testing reagent;

an upper support member upon which the matrix is mounted, having a slit which extends through the upper support member and permits visual observation of the test side;

a lower support member having a hole therethrough, said lower support member and said upper support member substantially surrounding the matrix;

said lower support member and said matrix defining a capillary gap therebetween which communicates with the hole and with a portion of the sample said opposite the slit;

said matrix, when applied on said sample side with a sample of whole blood suspected of containing glucose as an analyte, capable of accepting said whole blood sample through the hole so as to pass the sample toward said test said by capillary action;

said separation coating capable of separating from said whole blood a substantially clear component fluid containing said analyte by selectively retarding the passage of red blood cells through the matrix;

said testing reagent containing an indicator selected from the group consisting of alizarin cyanin green, bromopyrogallol red, anazolene sodium, pyrogallol red, and 2,2'"'"' azino-di-[3] ethylbenzthiazoline sulfonate, and capable of reacting with said analyte in said clear component fluid to vary coloration of the test side of said matrix, dependent upon the concentration level of the analyte in said fluid;

wherein said separation coating is selected from the group consisting of polyvinyl sulfonic acid, polyethylene glycol, polystyrene sulfonic acid, hydroxypropyl cellulose, polypropylene glycol, polyvinyl pyrrolidone and polyacrylic acid;

said matrix also has had coated to ti;

enzymes comprising glucose oxidase and horseradish peroxidase which react with said analyte;

a buffer selected from the group consisting of 2-(N-morpholine)-ethane acid, fumaric acid, malic acid, citric acid, and aconitic acid; and

an inhibitor selected from the group consisting of 2,3,4-trihydroxybenzoic acid, propyl gallate, ascorbic acid, isoascorbic acid, 3,4 dihydroxy cinnamic acid, 3,4 dihydroxy benzaldehyde, gallic acid, and 5,6 diaminouracil; and

said indicator and said inhibitor are present together on said matrix in bands, such that each band corresponds to one of two or more predetermined glucose concentrations and the presence of glucose concentrations in said whole blood sample which are equal to or grater than said predetermined concentrations may be detected by inspecting each band on the test side through said slit for variations in coloration.

6. The reagent strip of claim 5 wherein said bands are in 30 mg/dl intervals between 40 mg/dl and 400 mg/dl.

7. The reagent strip of claim 5 wherein said capillary gap is formed along one side of said matrix by a sheet of relatively impermeable material which has an elongated slit therein.