Minimum procedure system for the determination of analytes

• US 6,858,401 B2
• Filed: 09/23/2002
• Issued: 02/22/2005
• 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, Underwood, Ray, McGarraugh, Geoffery, Jurik, Frank
• Primary Examiner(s): GITOMER, RALPH J
• Application Number:
  US10/179,045
• Publication Number:
  US 20030054427A1
• Time in Patent Office: 883 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. The method and apparatus are particularly suitable for the measurement of glucose levels in blood without requiring separation of red blood cells from serum or plasma.

Claims

1. A method for determining glucose concentration, the method comprising:

applying an unmetered whole blood sample to a reagent test strip for use in an apparatus for determining the blood glucose concentration of a sample of whole blood, the apparatus including optical means for detecting intensity of light reflected from a reading surface portion of the reagent test strip, the reagent test strip comprising;

a sample receiving surface portion for receiving an unmeasured whole blood sample; and

a reading surface portion, other than the sample receiving surface portion, from which reflectance is read by the apparatus;

allowing the sample to migrate to the reading surface portion; and

monitoring the reflectance of the reading surface portion using the optical means of the apparatus;

wherein the applying of the unmetered whole blood sample occurs while the reagent test strip is in use in the apparatus.

2. The method of claim 1, wherein the monitoring step is performed without removing excess whole blood sample from the sample receiving surface portion.

3. The method claim 1, wherein the applying step applies an unmetered whole blood sample to the sample receiving surface portion, the sample receiving surface portion being on a different surface of the reagent test strip from the reading surface portion.

4. The method of claim 1, wherein the applying step is performed while the reading surface portion is in register with the optical means of the apparatus.

5. The method of claim 1 further comprising:

measuring, prior to the applying step, the reflectance of reading surface portion.

6. The method of claim 1, wherein the applying step includes applying an unmetered whole blood sample to a reagent test strip, at least portion of whose surface with the reading surface portion thereon is substantially reflective.

7. The method of claim 1, wherein the monitoring step monitors for a change in reflectance indicative of sample presence in the sample receiving surface portion in order to initiate timing of an incubation period;

and further comprising;

determining, after the monitoring step, a further change in reflectance at the reading surface portion during the incubation period as a measure of the concentration of blood glucose in the unmetered whole blood sample.