Metering technique for lateral flow assay devices

• US 7,803,319 B2
• Filed: 04/29/2005
• Issued: 09/28/2010
• Est. Priority Date: 04/29/2005
• Status: Expired due to Fees

• Current Assignee: Kimberly-Clark Worldwide Incorporated (Kimberly-Clark Corporation)
• Original Assignee: Kimberly-Clark Worldwide Incorporated (Kimberly-Clark Corporation)
• Inventors: Wei, Ning, Yang, Kaiyuan, Feaster, Shawn Ray
• Primary Examiner(s): Cook; Lisa V
• Application Number:
  US11/118,079
• Publication Number:
  US 20060246600A1
• Time in Patent Office: 1,978 Days
• Field of Search: 422/68.1, 422100-102, 422/104, 422/61, 422/946, 422/947, 435/4, 435/7.1, 435/283.1, 435/286.5, 435/287.1, 435/287.2, 435/287.7, 435/287.8
• US Class Current: 422/423
• CPC Class Codes: G01N 33/54366 Apparatus specially adapted for solid-phase testing
• 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

Abstract

A diagnostic test kit for detecting an analyte residing in a test sample is provided. The kit employs a lateral flow device that contains a membrane. A metering channel is formed in the membrane that is capable of delivering a controlled volume of the test sample to a detection zone upon initiation of the assay. Such a metering channel is particularly effective for embodiments in which the test sample has a relatively low volume, such as less than about 100 microliters, in some embodiments less than about 25 microliters, and in some embodiments, less than about 10 microliters. For example, whole blood drops obtained from patients with a lancet from low-pain areas (due to reduced nerve endings than finger), such as the forearm, thigh, or other alternate sites, may have a volume of from about 0.1 to about 5 microliters. Despite their low volume, the present inventors have discovered that the blood drops may still be accurately analyzed for the presence of an analyte using lateral flow detection techniques.

Claims

1. A diagnostic test kit for detecting the presence of an analyte within a test sample, the test kit comprising a lateral flow assay device that includes an elongated porous membrane and a conjugate pad, the conjugate pad comprising a plurality of detection probes conjugated with a specific binding member, the conjugated detection probes being capable of producing a detectable signal, the conjugate pad being in fluid communication with the membrane through which the test sample travels to reach a detection zone, wherein a metering channel is microfabricated into the membrane that has a width that is the same or substantially equal to the width of the membrane, wherein the metering channel is downstream from the conjugate pad, defined between opposing walls at least partially formed by the membrane and is configured for receiving the test sample, the depth of the metering channel being from about 0.1 to about 800 micrometers, and further wherein the detection zone is located downstream from the metering channel and a receptive material is immobilized within the detection zone that is capable of binding to the conjugated detection probes or complexes formed between the analyte and the conjugated detection probes.

2. The diagnostic test kit of claim 1, wherein the width of the metering channel is from about 0.5 to about 20 millimeters.

3. The diagnostic test kit of claim 1, wherein the width of the metering channel is from 2 to about 10 millimeters.

4. The diagnostic test kit of claim 1, wherein the depth of the metering channel is from about 80 to about 200 micrometers.

5. The diagnostic test kit of claim 1, wherein the length of the metering channel is less than about 20 millimeters.

6. The diagnostic test kit of claim 1, wherein the length of the metering channel is from about 0.01 to about 4 millimeters.

7. The diagnostic test kit of claim 1, wherein at least a portion of the metering channel contains a wetting agent.

8. The diagnostic test kit of claim 1, wherein at least a portion of the metering channel contains an agglutinating agent.

9. The diagnostic test kit of claim 1, further comprising a bridging member that is configured for placement over the metering channel and in fluid communication with the membrane, the test sample being capable of flowing through the bridging member.

10. The diagnostic test kit of claim 9, wherein the bridging member also functions as a blood separation filter.

11. The diagnostic test kit of claim 1, further comprising an absorbent member that is capable of being disposed within the metering channel.

12. The diagnostic test kit of claim 1, further comprising a liquid-impermeable support on which the membrane is disposed.

13. The diagnostic test kit of claim 12, wherein a bottom surface of the metering channel is defined by the support.

14. The diagnostic test kit of claim 1, wherein the membrane has a length of from about 10 to about 100 millimeters.

15. The diagnostic test kit of claim 1, wherein the membrane has a length of from about 20 to about 80 millimeters.

16. The diagnostic test kit of claim 1, wherein the membrane has a width of from about 0.5 to about 20 millimeters.

17. The diagnostic test kit of claim 1, wherein the membrane has a width of from about 2 to about 10 millimeters.

18. The diagnostic test kit of claim 1, wherein the microfabricated metering channel is formed by laser ablation.

19. The diagnostic test kit of claim 1, wherein the microfabricated metering channel is formed by solvent treatment.

20. The diagnostic test kit of claim 1, wherein at least one of the walls is a barrier to the flow of the test sample.

21. The diagnostic kit of claim 20, wherein at least one of the walls is generally free of a hydrophobic treatment.

22. The diagnostic test kit of claim 1, wherein the conjugated detection probes are in fluid communication with the membrane.