Assay test strips with multiple labels and reading same

• US 20070231922A1
• Filed: 09/26/2005
• Published: 10/04/2007
• Est. Priority Date: 04/01/2004
• Status: Active Grant

• Current Assignee: Alverix, Inc. (Becton, Dickinson & Co)
• Original Assignee: Alverix, Inc. (Becton, Dickinson & Co)
• Inventors: Roitman, Daniel, Zhou, Rong, Brosnan, Michael, Petrilla, John, Petruno, Patrick
• Granted Patent: US 7,521,259 B2
• Time in Patent Office: Days
• US Class Current: 436/514
• CPC Class Codes: G01N 2021/6441 with two or more labels
• 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 33/54388 based on lateral flow
• CPC Class Codes: G01N 33/558 using diffusion or migration of antigen or antibody immunochromatographic test strips G01N33/54387
• CPC Class Codes: Y10S 435/805 Test papers
• CPC Class Codes: Y10S 435/823 Acetobacter
• CPC Class Codes: Y10S 436/807 Apparatus included in process claim, e.g. physical support structures
• CPC Class Codes: Y10S 436/823 Immunogenic carrier or carrier per se
• CPC Class Codes: Y10T 436/25125 Digestion or removing interfering materials

Abstract

In one aspect, an assay test strip includes a test label that specifically binds a target analyte and a control label that is free of any specific binding affinity for the target analyte and has a different optical characteristic than the test label. In another aspect, an assay test strip includes a test label that specifically binds a target analyte and at least one non-specific-binding label that is free of any specific binding affinity for the target analyte. Systems and methods of reading assay test strips also are described.

Claims

1. An assay test strip, comprising:

a flow path for a fluid sample;

a sample receiving zone coupled to the flow path;

a test label that specifically binds a target analyte;

a control label that is free of any specific binding affinity for the target analyte and has a different optical characteristic than the test label; and

a detection zone coupled to the flow path downstream of the sample receiving zone and comprising an immobilized test reagent that specifically binds the target analyte and an immobilized control reagent that specifically binds the control label.

2. The assay test strip of claim 1, wherein the test label fluoresces at a first characteristic wavelength and the control label fluoresces at a second characteristic wavelength different from the first characteristic wavelength.

3. The assay test strip of claim 1, further comprising a test region containing the test reagent and a control region containing the control reagent.

4. The assay test strip of claim 3, wherein the control region is located downstream of the test region.

5. The assay test strip of claim 3, wherein the control region and the test region are equidistant from the sample receiving zone.

6. The assay test strip of claim 1, wherein the test label comprises quantum dots of a first type and the control label comprises quantum dots of a second type.

7. The assay test strip of claim 1, wherein the test reagent and the control reagent are immobilized in a combined test-and-control region of the detection zone.

8. The assay test strip of claim 7, wherein the test reagent and the control reagent are intermixed in the test-and-control region.

9. The assay test strip of claim 7, wherein the test reagent and the control reagent are located in separate contiguous sub-regions of the test-and-control region.

10. The assay test strip of claim 7, wherein the test-and-control region has a plano-elliptical shape.

11. The assay test strip of claim 1, wherein the test-and-control region has a plano-circular shape.

12. An assay test strip, comprising:

a flow path for a fluid sample;

a sample receiving zone coupled to the flow path;

a test label that specifically binds a target analyte;

at least one non-specific-binding label that is free of any specific binding affinity for the target analyte; and

a detection zone coupled to the flow path downstream of the sample receiving zone and comprising a first immobilized reagent that specifically binds the target analyte and a second immobilized reagent that specifically binds the test label, wherein each non-specific-binding label is free of any specific binding 11 affinity for any of the immobilized reagents in the detection zone.

13. The assay test strip of claim 12, wherein the test label fluoresces at a first characteristic wavelength and the non-specific-binding label fluoresces at a second characteristic wavelength different from the first characteristic wavelength.

14. The assay test strip of claim 13, wherein the test reagent and the control reagent are immobilized in a combined test-and-control region of the detection zone.

15. The assay test strip of claim 14, wherein the test reagent and the control reagent are intermixed in the test-and-control region.

16. The assay test strip of claim 14, wherein the test reagent and the control reagent are located in separate contiguous sub-regions of the test-and-control region.

17. A diagnostic test system, comprising:

an assay test strip comprising a detection zone and a flow path for a fluid sample along a lateral flow direction across the detection zone, wherein the detection zone comprises a capture region characterized by a first dimension transverse to the lateral flow direction and a second dimension parallel to the lateral flow direction; and

a reader comprising an illumination system operable to focus a beam of light onto an area of the detection zone having at least one surface dimension at most equal to smallest of the first and second dimensions of the capture region.

18. The system of claim 17, wherein the capture region has a plano-elliptical shape, and the illumination system is operable to focus a beam of light onto a plano-elliptical area of the detection zone substantially corresponding to the capture region in size and shape.

19. The system of claim 17, wherein the capture region has a plano-circular shape, and the illumination system is operable to focus a beam of light onto a plano-circular area of the detection zone substantially corresponding to the capture region in size and shape.

20. The system of claim 17, wherein the test strip comprises a first label that specifically binds a target analyte and fluoresces at a first characteristic wavelength and a second label that fluoresces at a second characteristic wavelength different from the first characteristic wavelength, and the detection zone comprises a first immobilized reagent that specifically binds the target analyte and a second immobilized reagent that specifically binds at least one of the second label and a second target analyte bound to the second label.

21. The system of claim 20, wherein the reader comprises a detection system operable to obtain light intensity measurements within a first wavelength range from an area of the detection zone corresponding to the first immobilized reagent and to obtain light intensity measurements within a second wavelength range from an area of the detection zone corresponding to the second immobilized reagent, the first wavelength range encompassing the first characteristic wavelength and excluding the second characteristic wavelength, and the second wavelength range encompassing the second characteristic wavelength and excluding the first characteristic wavelength.

22. The system of claim 17, wherein the first and second reagents are immobilized in the same capture region.

23. The system of claim 22, wherein the first and second reagents are intermixed in the same capture region.

24. The system of claim 22, wherein the first and second reagents are located in separate contiguous sub-regions of the same capture region.

25. The system of claim 22, wherein the detection system comprises an imaging sub-system operable to generate light intensity measurements from light and an optical sub-system operable to divide light from the detection zone into different spectral components and to direct the different spectral components to different areas of the imaging sub-system.

26. The system of claim 17, wherein the capture region contains the first immobilized reagent, and the detection zone comprises one or more additional capture regions containing the respective immobilized reagents.

27. The system of claim 26, further comprising a housing comprising a port constructed and arranged to receive the test strip, and wherein the detection system comprises at least two imaging devices that are disposed directly over respective ones of the capture regions when the test strip is loaded within the port.

28. A diagnostic test method, comprising:

receiving an assay test strip comprising a detection zone and a flow path for a fluid sample along a lateral flow direction across the detection zone, wherein the detection zone comprises a capture region characterized by a first dimension transverse to the lateral flow direction and a second dimension parallel to the lateral flow direction;

focusing a beam of light onto one or more areas of the detection zone having at least one surface dimension at most equal to smallest of the first and second dimensions of the capture region; and

obtaining light intensity measurements from the illuminated areas of the 11 detection zone.

29. A diagnostic test system, comprising:

a reader operable to obtain light intensity measurements from exposed regions of an assay test strip comprising a detection zone; and

a data analyzer operable to perform operations comprising determining a test measurement value from light intensity measurements obtained from a test label bound to a region in the detection zone containing a first immobilized reagent, determining a compensation measurement value from light intensity measurements obtained from a compensation label different from the test label in one or more regions of the detection zone free of immobilized reagents that specifically bind the compensation label, and determining a parameter value from the test measurement value and the compensation measurement value.

30. The system of claim 29, wherein the data analyzer is operable to determine the parameter value based on a ratio of the test measurement value and the compensation measurement value.

31. The system of claim 29, wherein the data analyzer is operable to determine the parameter value based on a difference between the test measurement value and the compensation measurement value.

32. The system of claim 29, wherein the data analyzer is operable to determine the parameter value based on a comparison of the test measurement value relative and the compensation measurement value relative to a threshold.

33. A diagnostic test system, comprising:

obtaining light intensity measurements from exposed regions of an assay test strip comprising a detection zone;

determining a test measurement value from light intensity measurements obtained from a region in the detection zone containing a test label bound to a first immobilized reagent;

determining a compensation measurement value from light intensity measurements obtained from a compensation label different from the test label in one or more regions of the detection zone free of immobilized reagents that specifically bind the compensation label; and

determining a parameter value from the test measurement value and the compensation measurement value.