APPARATUS AND METHOD FOR IDENTIFYING A HOOK EFFECT AND EXPANDING THE DYNAMIC RANGE IN POINT OF CARE IMMUNOASSAYS

• US 20140186216A1
• Filed: 12/27/2013
• Published: 07/03/2014
• Est. Priority Date: 12/28/2012
• Status: Active Grant

• Current Assignee: Abbott Point Of Care Incorporated (Abbott Laboratories Incorporated)
• Original Assignee: Abbott Point Of Care Incorporated (Abbott Laboratories Incorporated)
• Inventors: Dowell, Barry Lee, Campbell, John, Nguyen, Linda, Smith, James, Weiss, Wenda
• Granted Patent: US 9,671,398 B2
• Time in Patent Office: Days
• US Class Current: 422/69
• CPC Class Codes: G01N 33/5306 Improving reaction conditions, e.g. reduction of non-specific binding, promotion of specific binding
• CPC Class Codes: G01N 33/54366 Apparatus specially adapted for solid-phase testing
• CPC Class Codes: G01N 33/5438 Electrodes
• CPC Class Codes: G01N 33/54393 Improving reaction conditions or stability, e.g. by coating or irradiation of surface, by reduction of non-specific binding, by promotion of specific binding

Abstract

The present invention relates to systems and methods for the rapid in situ determination of the existence of a hook effect and expansion of the dynamic range of a point of care immunoassay. For example, a system for identifying a hook effect and expanding the dynamic range of an immunoassay is provided that may include a primary sensor having first immobilized antibodies that may be configured to generate a first signal based on a presence or absence of a target analyte in a sample. The system may further include an attenuated sensor having second immobilized antibodies at a reduced concentration relative to a concentration of the first immobilized antibodies on the primary sensor and that may be configured to generate a second signal based on the presence or absence of the target analyte in the sample. The system may further include a processor configured to determine a presence of a hook effect in the immunoassay based on relative values of the first and second signals and optionally determine the target analyte concentration of the sample.

Claims

1. A system for identifying a hook effect, the system comprising:

a first capture reagent comprising an antigen-binding reagent configured to generate a first signal based on a presence or absence of a target analyte in a sample;

a second capture reagent comprising an attenuated antigen-binding reagent at a reduced concentration relative to a concentration of the antigen-binding reagent and configured to generate a second signal based on the presence or absence of the target analyte in the sample; and

a processor configured to determine a presence of a hook effect in an assay based on relative values of the first and second signals.

2. The system of claim 1, wherein the first capture reagent is printed on a first site and the second capture reagent is printed on a second site different from the first site.

3. The system of claim 1, wherein the target analyte binding to the first capture reagent and the second capture reagent is detected by color formation or fluorescence detection.

4. The system of claim 1, wherein the antigen-binding reagent and the attenuated antigen-binding reagent are immobilized on microparticles.

5. The system of claim 1, wherein the first capture reagent and the second capture reagent are printed on a same site located on a conduit of an analysis cartridge.

6. The system of claim 5, wherein the antigen-binding reagent is labeled with a first color or fluorescent dye and the attenuated antigen-binding reagent is labeled with a second color or fluorescent dye different from the first color.

7. The system of claim 1, wherein the attenuated antigen-binding reagent and a co-absorbate are immobilized on microparticles over an attenuated sensor.

8. The system of claim 7, wherein the antigen-binding reagent is immobilized on microparticles over a primary sensor and said microparticles adsorbed on said primary sensor do not comprise the co-absorbate.

9. The system of claim 7, wherein the co-absorbate dilutes surface activity of the attenuated antigen-binding reagent on the microparticles adsorbed over the attenuated sensor.

10. The system of claim 7, wherein the presence of the co-absorbate on the microparticles over the attenuated sensor provides the reduced concentration of the second immobilized antibodies relative to the concentration of first immobilized antibodies.

11. The system of claim 7, wherein the co-absorbate comprises non-specific antibodies and/or proteins.

12. The system of claim 11, wherein the non-specific antibodies comprise mouse IgG or goat IgG.

13. The system of claim 11, wherein the proteins comprise bovine serum albumin (BSA) or human serum albumin (HSA).

14. The system of claim 1, wherein the processor is further configured to determine a concentration of the target analyte based on the presence of the hook effect and the relative values of the first and second signals.

15. A system for identifying a hook effect in an assay, the system comprising:

a first immobilized antibody configured to generate a first signal based on a sandwich between the first immobilized antibody, a target analyte, and a labeled antibody;

a second immobilized antibody at a reduced concentration relative to a concentration of the first immobilized antibody and configured to generate a second signal based on a sandwich between the second immobilized antibody, the target analyte, and the labeled antibody; and

a processor configured to determine a presence of a hook effect in the immunoassay based on relative values of the first and second signals.

16. The system of claim 15, wherein the first immobilized antibodies comprise a first affinity for the target analyte and the second immobilized antibodies comprise a second affinity for the target analyte, the first affinity being different from the second affinity.

17. The system of claim 15, wherein the first and second immobilized antibodies are the same antibodies.

18. The system of claim 15, wherein the labeled antibody is labeled with alkaline phosphatase (ALP).

19. The system of claim 15, wherein the labeled antibody is labeled with alkaline phosphatase (ALP) and the first and second signals are generated at a primary immunosensor and an attenuated immunosensor respectively from an electroactive species with a phosphate moiety that is cleaved by the ALP.

20. The system of claim 19, wherein the primary immunosensor and the attenuated immunosensor are disposed in a disposable cartridge that is configured to perform the assay to determine a presence of the target analyte in a sample.

21. The system of claim 20, wherein the sample comprises a blood sample.

22. The system of claim 15, wherein the target analyte is prostate specific antigen (PSA).

23. The system of claim 15, wherein the first immobilized antibody is printed on a first site and the second immobilized antibody is printed on a second site different from the first site.

24. The system of claim 15, wherein the target analyte binding to the first immobilized antibody and the second immobilized antibody is detected by color formation or fluorescence detection.

25. The system of claim 15, wherein the first immobilized antibody and the second immobilized antibody are immobilized on microparticles.