Method and apparatus for analyte detection having on-strip standard

• US 5,780,304 A
• Filed: 03/11/1996
• Issued: 07/14/1998
• Est. Priority Date: 09/08/1994
• Status: Expired due to Term

• Current Assignee: Lifescan Incorporated (Duv Holding Corporation)
• Original Assignee: Lifescan Incorporated (Duv Holding Corporation)
• Inventors: Matzinger, David Parkes, Daffern, George Michael
• Primary Examiner(s): ALEXANDER, LYLE
• Application Number:
  US08/613,404
• Time in Patent Office: 855 Days
• Field of Search: 422/68.1, 422/82.05, 422/56, 422/58, 436/169
• US Class Current: 436/169
• CPC Class Codes: G01N 2021/8488 the band presenting reference patches
• 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 33/521 Single-layer analytical elements

Abstract

A test strip is provided for having liquid applied thereto and for determining the presence or quantity of an analyte in such liquid. Specifically, the test strip comprises a reaction zone which varies in reflectance as a function of the quantity of analtye present in the applied liquid. The strip is to be inserted into an optical reading apparatus. A standard zone is positioned on the strip so as to lead the reaction zone as the strip is inserted into the reading apparatus. The apparatus may then be provided with optical means for sequentially determining the reflectance value of the standard zone as the strip is being inserted into its fully inserted position in the apparatus and the reflectance value of the reaction zone after the strip has been inserted. The apparatus is further provided with means for calculating the presence and/or quantity of analyte in question as a function of the standard zone reflectance and the reaction zone reflectance.

Claims

1. An apparatus for determining the presence or quantity of an analyte in a sample applied to a portion of a longitudinally extending test strip;

said portion having an optically visible surface defining a reaction zone which reaction zone varies in reflectance as a function of the quantity of analyte present in the applied liquid;

said apparatus comprising;

an opening for inserting the leading edge of said strip into said apparatus;

a strip passageway extending from said opening and terminating at a strip impeding means for impeding the strip after it is fully inserted;

an optical aperture through said passageway whereby a portion of the surface of the strip overlying said aperture is visible, said aperture positioned along said passageway so that when said strip is fully inserted said reaction zone of said strip is visible therethrough;

optics, in optical communication with said optical aperture, said optics comprising at least one light source for directing light onto said portion of said strip and at least one reflectance detector for detecting light reflected from said portion of said strip;

a microprocessor for controlling the optics as the strip is being inserted into the passageway and after the strip has reached the strip impeding means;

said microprocessor being programmed to cause said light source and detector to make a plurality of readings of a standard zone provided on the surface of the strip leading the reaction zone and visible through the optical aperture as the strip is being inserted, and use the highest reading to provide a calibrated standard reflectance;

said microprocessor being programmed to cause said light source and said detector to read the reflectance of the reaction zone after the strip has been inserted; and

said microprocessor being programmed to determine the quantity of analyte in the sample as a function of said calibrated standard zone reflectance and the reflectance of the reaction zone; and

means for reporting such quantity.

2. A method for determining the presence or quantity of an analyte in a liquid applied to a test strip and inserted into an optical reading apparatus, said method comprising:

applying liquid to said test strip wherein said test strip comprises a portion having a surface defining a reaction zone which varies in reflectance as a function of the quantity of analyte present in said applied liquid and further comprises a standard zone of substantially constant reflectance;

inserting said strip into said apparatus with said standard zone leading said reaction zone as said strip is inserted;

taking a plurality of readings of the reflectance of said standard zone as said strip is inserted;

reading the reflectance of said reaction zone after said strip is inserted;

employing the highest of the standard zone reflectance readings and the reaction zone reflectance reading to determining the presence or quantity of the analyte in the liquid as a function of these reflectance readings.

3. The method of claim 2 where at least three readings are taken of the standard zone.