Apparatus for determinating the concentration of glucose in whole blood

• US 6,489,133 B2
• Filed: 02/15/2001
• Issued: 12/03/2002
• Est. Priority Date: 08/13/1986
• Status: Expired due to Fees

• Current Assignee: Lifescan Incorporated (Duv Holding Corporation)
• Original Assignee: Lifescan Incorporated (Duv Holding Corporation)
• Inventors: Phillips, Roger, McGarraugh, Geoffery, Jurik, Franklin A., Underwood, Raymond D.
• Primary Examiner(s): GITOMER, RALPH J
• Application Number:
  US09/784,993
• Publication Number:
  US 20010019831A1
• Time in Patent Office: 656 Days
• Field of Search: 435/14, 435/28, 422/56-58
• US Class Current: 435/14
• CPC Class Codes: C12Q 1/54 involving glucose or galactose
• CPC Class Codes: G01N 2021/4757 Geometry 0/45° or 45/0°
• CPC Class Codes: G01N 21/314 with comparison of measurements at specific and non-specific wavelengths dual wavelength spectrometry G01J3/427
• CPC Class Codes: G01N 21/4738 Diffuse reflection precedence is given to G01N21/55 - G01N21/57 if specular component is taken into consideration, e.g. also for testing fluids, fibrous materials
• CPC Class Codes: G01N 21/8483 Investigating reagent band test-element handling not specific to a test method G01N33/4875; analytical elements specific to chemical analysis of biological material G01N33/52; autometer with reagent band G01N35/04
• CPC Class Codes: G01N 33/52 Use of compounds or compositions for colorimetric, spectrophotometric or fluorometric investigation, e.g. use of reagent paper and including single- and multilayer analytical elements immunological elements G01N33/54386; involving labelled immunochemicals G01N33/58; for haemoglobin or occult blood G01N33/72
• 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: G01N 33/66 involving blood sugars, e.g. galactose
• CPC Class Codes: G01N 35/1016 Control of the volume dispensed or introduced
• CPC Class Codes: Y02A 90/10 Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation
• CPC Class Codes: Y10S 435/805 Test papers
• CPC Class Codes: Y10S 435/808 Optical sensing apparatus
• CPC Class Codes: Y10S 435/81 Packaged device or kit
• CPC Class Codes: Y10T 436/112499 with sample on test slide
• CPC Class Codes: Y10T 436/144444 Glucose

Abstract

A method for determining the presence of an analyte in a fluid is described along with various components of an apparatus specifically designed to carry out the method. The method involves taking a reflectance reading from one surface of an inert porous matrix impregnated with a reagent that will interact with the analyte to produce a light-absorbing reaction product when the fluid being analyzed is applied to another surface and migrates through the matrix to the surface being read. Reflectance measurements are made at two separate wavelengths in order to eliminate interferences, and a timing circuit is triggered by an initial decrease in reflectance by the wetting of the surface whose reflectance is being measured by the fluid which passes through the inert matrix. Repeatability is insured by a normalization technique performed on the light source before each reading, and an alignment method operated on the reagent strip prior to emplacement on the apparatus. The method and apparatus are particularly suitable for the measurement of flucose levels in blood without requiring separation of red blood cells from serum or plasma.

Claims

1. An apparatus for measuring the concentration of glucose in a sample of whole blood, which comprises:

(a) a chamber for removably accepting a test strip that includes a porous matrix pad which

(1) has a first major surface for accepting the sample and a reflective second major surface opposite to the first surface,

(2) allows a portion of the sample to travel through the pad from the first surface toward the second surface, and

(3) is impregnated with a reagent that reacts with glucose to cause a change in the reflectance at the second surface;

(b) means for illuminating the second surface of the pad in the chamber;

(c) means for monitoring intensity of light reflected from the second surface of the pad in the chamber;

(d) means for taking a sequence of reflectance readings from the second surface of said matrix at specified time intervals upon detecting a predetermined drop in reflectance sufficient to indicate that said sample has reached said first surface; and

(e) means for calculating said glucose concentration in said sample from one of said reflectance readings upon detection of a suitably stable endpoint, without having determined the time at which sample was initially applied to the matrix pad.

2. The apparatus according to claim 1, wherein said porous matrix comprises polyamide.

3. The apparatus according to claim 1, wherein said porous matrix is positively charged.

4. The apparatus according to claim 1, wherein said porous matrix is negatively charged.

5. The apparatus according to claim 1, wherein said porous matrix is functionalized with functional groups selected from the group consisting of quarternary amine groups and carboxyl groups.

6. The apparatus according to claim 1, wherein said porous matrix has an average pore size ranging of from about 0.1 to 3.0 microns.

7. The apparatus according to claim 1, wherein said porous matrix has a thickness less than about 0.5 mm.

8. The apparatus according to claim 1, wherein said signal producing system comprises glucose oxide, peroxidase, and a dye indicator.

9. The apparatus according to claim 8, wherein said dye indicator is at least one dye indicator selected from the group consisting of 3-methyl-2-benzothiazolinone hydrazone hydrochloride, 3-dimethylaminobenzoic acid, 4-aminoantipyrene and chromotropic acid.

10. The apparatus according to claim 1, wherein said porous matrix further comprises a buffer.

11. The apparatus according to claim 10, wherein said buffer is citrate buffer.