Claims
- 1. A test strip comprising
(a) a first membrane comprising a chromatographic strip having a first end and a second end; and (b) a sample filter having an upper surface and a lower surface, wherein the lower surface of the sample filter is in capillary contact with the chromatographic strip; wherein the sample filter is capable of separating cells in a sample from fluid in the sample and allows the fluid to pass through to the chromatographic strip, and further wherein the test strip facilitates lateral flow of fluid from the sample filter towards the second end of the chromatographic strip.
- 2. The test strip of claim 1, wherein the sample filter comprises pores of varying sizes and wherein cells in the sample are retained by the sample filter and fluid in the sample passes through the sample filter.
- 3. The test strip of claim 2, wherein the sample filter comprises first pores having a first pore size and second pores having a second pore size, wherein the first pores are larger than the second pores and further wherein the first pores are closer to the upper surface of the sample filter and the second pores are closer to the lower surface of the sample filter.
- 4. The test trip of claim 1, further comprising (c) a sample pad close to the first end of the chromatographic strip and wherein the sample pad allows the fluid to pass through to the chromatographic strip, and further wherein the test strip supports lateral flow of fluid in the sample from the sample pad towards the second end of the chromatographic strip.
- 5. The test strip of claim 3, further comprising (c) sample pad comprising an upper surface and a lower surface, wherein the lower surface of the sample pad is in capillary contact with the chromatographic strip and wherein the lower surface of the sample filter is in capillary contact with the upper surface of the sample pad and further wherein the test strip supports lateral flow of fluid in the sample from the sample pad towards the second end of the chromatographic strip.
- 6. The test strip of claim 4, further comprising a selective membrane in capillary contact with the sample filter and the sample pad.
- 7. The test strip of claim 6, wherein the selective membrane is positioned under the sample filter.
- 8. The test strip of claim 6, wherein the selective membrane is positioned on top of the sample pad or on top of the chromatographic strip.
- 9. The test strip of claim 6, wherein the selective membrane contains an agent that selectively binds to a component in the sample and removes the component from the assay environment.
- 10. The test strip of claim 9, wherein the agent is selected from the group consisting of an antibody, an antigen, a metabolite, a hormone, an enzyme, a virus, a prion, or parts thereof, and an agent that binds to such.
- 11. The test strip of claim 1, further comprising one or more filters or membrane positioned between the sample filter and the chromatographic strip.
- 12. The test strip of claim 4, further comprising
(d) a conjugate pad comprising an upper surface and a lower surface, wherein the conjugate pad is at or near the second end of the chromatographic strip and wherein the lower surface of the conjugate pad is in capillary contact with the chromatographic strip; (e) a reagent pad comprising an upper surface and a lower surface, wherein the lower surface of the reagent pad is in capillary contact with the upper surface of the conjugate pad; and (f) an absorbent pad at the first end of the chromatographic strip and to a side of the sample pad that is away from the conjugate pad, wherein the absorbent pad is in capillary contact with the chromatographic strip; and wherein the sample filter is capable of separating the cells from the fluid in the sample and the test strip supports lateral flow of fluid in the sample from the sample pad towards the conjugate pad.
- 13. The test strip of claim 12, wherein the reagent pad further comprises a reagent.
- 14. The test strip of claim 13, wherein the reagent is a buffer.
- 15. The test strip of claim 12, wherein the conjugate pad comprises a conjugate that can be released from the conjugate pad upon application of fluid to the conjugate pad, wherein the conjugate is capable of combining with an analyte to be detected to form a detectable signal.
- 16. The test strip of claim 12, wherein the conjugate comprises a first binding agent that is capable of binding to an analyte.
- 17. The test strip of claim 16, wherein the first binding agent is an antibody or antigen.
- 18. The test strip of claim 16, wherein the conjugate further comprises a second binding agent.
- 19. The test strip of claim 18, wherein the second binding agent comprises a detectable marker that binds either to the first binding agent or to the analyte.
- 20. The test strip of claim 19, wherein the detectable marker is quantifiable.
- 21. The test strip of claim 15, the conjugate flows from the conjugate pad to come into contact with the fluid from the sample and forms an immobilized complex.
- 22. The test strip of claim 15, wherein the conjugate pad is situated between the sample filter and the second end of the chromatographic strip, and the flow of fluid from the sample filter to the conjugate pad to releases the conjugate from the conjugate pad.
- 23. The test strip of claim 15, wherein the conjugate pad is situation under the sample filter and is in capillary contact with the sample filter.
- 24. The test strip of claim 1, wherein the chromatographic strip further comprises an adhesive layer and a backing for the adhesive layer.
- 25. The test strip of claim 1, wherein the membrane comprises nitrocellulose.
- 26. The test strip of claim 1, wherein the sample filter is a blood cell/plasma separation membrane.
- 27. The test strip of claim 1, wherein the sample comprises fluid and cells.
- 28. The test strip of claim 1, wherein the sample is a blood sample, a saliva sample, a urine sample, sample taken from lymphatic tissues, a sample from a spinal tap, or a sample taken from a peritoneal cavity, synovial fluid from a joint, or fluid from lungs.
- 29. The test strip of claim 1, wherein the sample comprises red blood cells.
- 30. The test strip of claim 1, wherein the sample filter comprises a hydrophilic surface that contacts the sample.
- 31. The test strip of claim 1, wherein the sample filter comprises an S/G membrane.
- 32. A method of making a test strip comprising the steps of
(a) providing a chromatographic strip having a first end and a second end; and (b) providing a sample filter having an upper surface and a lower surface, wherein the lower surface of the sample filter is in capillary contact with the chromatographic strip; wherein the sample filter is capable of separating cells in a sample from fluid in the sample and allows the fluid to pass through to the chromatographic strip, and further wherein the test strip facilitates lateral flow of fluid from the sample filter towards the second end of the chromatographic strip.
- 33. The method of claim 32, further comprising the step of
(c) placing a sample pad between the sample filter and the chromatographic strip, wherein the sample pad is in capillary contact with the sample filter and the chromatographic strip, and fluid flows from the sample filter through the sample pad to the chromatographic strip by capillary or osmotic forces.
- 34. The method of claim 33, further comprising the step of
(d) providing a conjugate pad on the chromatographic strip, wherein the conjugate pad is in capillary contact with the chromatographic strip, and fluid flows through the conjugate pad to the chromatographic strip by capillary or osmotic forces.
- 35. The method of claim 34, further comprising the step of
(e) providing a reagent pad on the conjugate pad, wherein the reagent pad is in capillary contact with the conjugate pad and allows the flow of fluid from the reagent pad to the conjugate pad.
- 36. The method of claim 35, further comprising the step of
(f) providing a selective membrane between the sample filter and the chromatographic strip, where the selective membrane is in capillary contact with the sample filter and the chromatographic strip and allows the flow of fluid from the sample filter to the chromatographic strip.
- 37. A method of separating cells from fluid in a sample for conducting a lateral flow assay for detection of an analyte in the sample, comprising the steps of:
(a) providing a test strip according to claim 1; and (b) applying the sample on the sample filter, thereby separating cells from fluid in a sample.
- 38. A method of conducting a lateral flow assay for detection of an analyte in a sample that contains cells and fluid, comprising the steps of:
(a) providing a test strip according to claim 15;(b) applying the sample to the sample filter; (c) allowing flow of fluid from the sample filter to the chromatographic strip and towards the second end of the chromatographic strip; (d) applying a buffer to release the conjugate in the conjugate pad; (e) allowing flow of the conjugate towards the analyte in the sample to form a complex; and (f) detecting presence of the complex.
- 39. The method of claim 38, further comprising the step of:
(g) quantifying amount of complex formed.
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is related to U.S. Provisional Patent Application Serial No. 60/306,660, entitled “A Test Strip for Lateral Flow Assay for a Sample Containing Whole Cells,” filed Jul. 18, 2001, from which priority is claimed under 35 USC §119(e)(1), and which application is incorporated herein by reference in its entirety.
Provisional Applications (1)
|
Number |
Date |
Country |
|
60306660 |
Jul 2001 |
US |