METHOD TO INCREASE SPECIFICITY AND/OR ACCURACY OF LATERAL FLOW IMMUNOASSAYS

• US 20100112725A1
• Filed: 09/29/2009
• Published: 05/06/2010
• Est. Priority Date: 02/09/2005
• Status: Active Grant

• Current Assignee: Rapid Pathogen Screening, Inc
• Original Assignee: Rapid Pathogen Screening, Inc
• Inventors: Scheibenzuber, Marcus, Sambursky, Robert P., VanDine, Robert W., Babu, Uma Mahesh, Sambursky, Jose S., Aberl, Franz
• Granted Patent: US 8,445,293 B2
• Time in Patent Office: Days
• US Class Current: 436/518
• CPC Class Codes: G01N 33/54388 based on lateral flow
• 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
• CPC Class Codes: G01N 33/558 using diffusion or migration of antigen or antibody immunochromatographic test strips G01N33/54387
• CPC Class Codes: G01N 33/6893 related to diseases not provided for elsewhere
• CPC Class Codes: Y10T 436/142222 Hetero-O [e.g., ascorbic acid, etc.]
• CPC Class Codes: Y10T 436/173845 Amine and quaternary ammonium
• CPC Class Codes: Y10T 436/25 including sample preparation
• CPC Class Codes: Y10T 436/25125 Digestion or removing interfering materials
• CPC Class Codes: Y10T 436/25375 Liberation or purification of sample or separation of material from a sample [e.g., filtering, centrifuging, etc.]

Abstract

The present invention includes methods and devices for preventing interfering substances from affecting the accuracy of a lateral flow immunoassay. In preferred embodiments, a test strip includes a capturing zone that includes at least one mobile capturing reagent that separates at least one interfering substance from the analyte. The capturing zone is preferably located upstream of the sample application zone. In some embodiments, the reagent/conjugate zone is also located upstream of the sample application zone. The capturing zone may be located upstream, downstream, or overlapping with the reagent/conjugate zone in these embodiments. In other preferred embodiments, one or more mobile capturing reagents are included in the elution medium/running buffer. In yet other embodiments, the capturing reagent is incorporated into a sample collection device of a sample collection system, preferably separate from the chromatographic test strip. A lysis zone is also included in some preferred embodiments.

Claims

1. A method for detecting an analyte in a sample, comprising the steps of:

a) applying the sample to a sample application zone of a chromatographic carrier;

b) eluting at least one mobile capturing reagent located in a capturing zone, wherein the capturing zone is located upstream of the sample application zone on the chromatographic carrier, such that the mobile capturing reagent travels downstream to encounter the sample;

c) if at least one interfering substance is present in the sample, capturing the interfering substance, wherein the mobile capturing reagent interacts with the interfering substance and separates the interfering substance from the analyte; and

d) detecting the analyte separated from the interfering substance on the carrier.

2. The method of claim 1, wherein the chromatographic carrier further comprises:

i) a reagent zone containing reagents for detecting the analyte, wherein the sample and the reagents encounter each other while a test for detecting the analyte is being performed; and

ii) a detection zone for detecting the analyte, wherein the detection zone is located downstream of the sample application zone.

3. The method of claim 2, wherein the reagent zone is located upstream of the sample application zone.

4. The method of claim 3, wherein the reagent zone overlaps the capturing zone.

5. The method of claim 3, wherein the reagent zone is located upstream of the capturing zone.

6. The method of claim 3, wherein the reagent zone is located downstream of the capturing zone.

7. The method of claim 2, wherein the method is used to detect conjunctivitis and, in step a), an eye fluid sample collected on a sterile swab member is applied to the chromatographic carrier by directly contacting the swab member with the sample application zone without pretreatment of the sample wherein at least a part of the eye fluid sample is released directly into the sample application zone due to the swab member contacting the sample application zone.

8. The method of claim 2, wherein the capturing zone comprises a mobile capturing reagent which specifically interacts with the interfering substance, thereby complexing with the interfering substance.

9. The method of claim 1, further comprising, prior to step a), the step of collecting the sample with a collection device.

10. The method of claim 1, wherein the sample is a body fluid selected from blood, serum or a body surface fluid.

11. The method of claim 10, wherein the body fluid is an eye fluid, sweat or saliva.

12. The method of claim 1, wherein the analyte is detected by an immune reaction.

13. The method of claim 1, wherein the analyte is a pathogen or a plurality of pathogens.

14. The method of claim 13, wherein the analyte is a pathogen or a plurality of pathogens associated with conjunctivitis.

15. The method of claim 14, wherein the pathogen is selected from the group consisting of adenoviruses, herpesviruses, chlamydiae, cytomegaloviruses, pseudomonas, streptococci, haemophilus, staphylococci, amoebae and combinations thereof.

16. The method of claim 1, wherein the analyte is a low-molecular-weight compound.

17. The method of claim 16, wherein the interfering substance is a low molecular-weight drug molecule which exhibits structural similarity with the analyte.

18. The method of claim 16, wherein the analyte is heroin or 6-monoacetylmorphine and the interfering substance is another opiate like morphine, codeine or dihydrocodeine.

19. The method of claim 16, wherein the analyte is methamphetamine and the interfering substance is a structural similar compound like amphetamine, Ecstasy or ephedrine.

20. The method of claim 1, wherein the interfering substance is captured and thereby separated from the analyte by an immune reaction.

21. The method of claim 20, wherein the immune reaction comprises the interfering substance complexing with a mobile capturing reagent.

22. The method of claim 1, wherein the interfering substance is an antibody.

23. The method of claim 22, wherein the antibody is a human anti-mouse antibody (HAMA).

24. The method of claim 23, wherein the human anti-mouse antibody (HAMA) is separated from the analyte by an immune reaction with a monoclonal or a polyclonal mouse antibody.

25. The method of claim 1, wherein the interfering substance is selected from the group consisting of at least one heterophilic antibody;

at least one rheumatoid factor (RF); and

both at least one heterophilic antibody and at least one rheumatoid factor.

26. The method of claim 1, wherein the carrier further comprises a waste zone.

27. The method of claim 1, wherein the carrier is a chromatographic test strip.

28. A test strip for detecting an analyte in a sample, comprising:

a) an application zone, wherein the sample is applied to the application zone;

b) a reagent zone comprising at least one first reagent, wherein the sample and the first reagent encounter each other while a test for detecting the analyte is being performed and wherein the first reagent interacts with the analyte to form a first complex;

c) a capturing zone, wherein the capturing zone comprises at least one mobile capturing reagent that is capable of interacting with at least one interfering substance in the sample such that the capturing reagent separates the interfering substance from the analyte, wherein the capturing zone is located upstream of the application zone; and

d) a detection zone comprising at least one test zone comprising at least one second reagent, wherein the second reagent complexes with and immobilizes the analyte at the test zone and wherein the detection zone is located downstream of the application zone.

29. The test strip of claim 28, wherein the reagent zone is located upstream of the application zone.

30. The test strip of claim 29, wherein the reagent zone overlaps the capturing zone.

31. The test strip of claim 29, wherein the reagent zone is located upstream of the capturing zone.

32. The test strip of claim 29, wherein the reagent zone is located downstream of the capturing zone.

33. A test kit for detecting an analyte in a sample comprising:

a) a chromatographic test strip comprising;

i) an application zone, wherein the sample is applied to the application zone;

ii) a reagent zone comprising at least one first reagent, wherein the sample and the first reagent encounter each other while a test for detecting the analyte is being performed and wherein the first reagent interacts with the analyte to form a first complex; and

iv) a detection zone comprising at least one test zone comprising at least one second reagent, wherein the second reagent complexes with and immobilizes the analyte at the test zone and wherein the detection zone is located downstream of the application zone; and

b) at least one sample collection system comprising at least one sample collection device and at least one mobile capturing reagent that is incorporated into at least one sample application device, wherein the mobile capturing reagent is capable of interacting with at least one interfering substance in the sample such that the capturing reagent separates the interfering substance from the analyte, wherein the collection system collects the sample prior to the sample being transferred to the chromatographic test strip.

34. The test kit of claim 33, wherein the reagent zone is located upstream of the application zone.

35. The test kit of claim 33, wherein the sample collection system comprises one sample collection device and the capturing reagent is incorporated into the sample collection device.

36. The test kit of claim 33, wherein the sample collection system comprises a first sample collection device and a second sample collection device, wherein the first sample collection device collects the sample and the second sample collection device comprises the mobile capturing reagent, wherein the sample is transferred from the first sample collection device to the second sample collection device before being transferred to the chromatographic test strip.

37. A method for detecting an analyte in a sample, comprising the steps of:

a) collecting a sample with at least one sample collection system, wherein the sample collection system comprises at least one sample collection device and at least one capturing reagent that is incorporated into at least one sample collection device;

b) applying the sample and the capturing reagent to a sample application zone of a chromatographic carrier;

c) if at least one interfering substance is present in the sample, capturing the interfering substance, wherein the mobile capturing reagent interacts with the interfering substance and separates the interfering substance from the analyte; and

d) detecting the analyte separated from the interfering substance on the carrier.

38. The method of claim 37, wherein the capturing reagent is incorporated into the sample collection device that collects the sample.

39. The method of claim 37, wherein the sample collection system comprises a first sample collection device and a second collection device, wherein the first sample collection device collects the sample and the second collection device comprises the mobile capturing reagent, wherein the sample is transferred from the first sample collection device to the second collection device before being applied to the chromatographic test strip.