Combined visual/fluorescence analyte detection test
View Patent ↗The sensitivity of visually read lateral flow immunoassay tests is enhanced by adding a small quantity of fluorescing dye or fluorescing latex bead conjugates to the initial conjugate material. When the visible spectrum test line is visibly present, the test result is observed and recorded. However, in the case where the result is indeterminate, a light of an appropriate spectrum, such as a UV, visible, or infrared spectrum, is cast on the test line to excite and fluoresce the fluorescing latex beads which are bound in the test line in true positive tests to enhance the visible color at the test line.
1. A method of running an assay on a sample, comprising the steps of:
a) transferring the sample to a sample analysis device, wherein the sample analysis device comprises a plurality of labels visible to an unaided eye and a plurality of fluorescing elements, wherein the labels and the fluorescing elements are each coupled with at least one specific binding partner for a target in the sample; and
b) analyzing the sample for a presence of at least one target, comprising the substeps of,
i) determining if a label is visible to the unaided eye at a test zone of the sample analysis device; and
ii) if a visibility of the label is indeterminate, casting a fluorescent light source on the test zone to determine whether a result is positive using fluorescence.
2. The method of claim 1 , wherein the specific binding partner comprises an antibody or an antigen.
3. The method of claim 1 , further comprising, before step a), the step of collecting the sample.
4. The method of claim 1 , wherein substep ii) enhances a sensitivity of the method at least tenfold compared to a method that only uses a visual-label to determine a result.
5. The method of claim 1 , wherein step b) is performed within 10 minutes of transferring the sample to the sample analysis device.
6. The method of claim 1 , wherein step b) is performed within 10 minutes of transferring the sample to the sample analysis device.
7. The method of claim 1 , wherein the labels visual to the unaided eye are selected from the group consisting of a plurality of colloidal gold particles; a plurality of dyed latex beads; a plurality of selenium particles; and a plurality of carbon particles.
8. The method of claim 1 , wherein the fluorescing element is a fluorescing dye.
9. The method of claim 1 , wherein the fluorescing element comprises a plurality of colorless fluorescing latex beads.
10. The method of claim 9 , wherein a volume of the fluorescing latex beads coupled with the specific binding partner is approximately 0.1% to 10% of a volume of the labels visible to the unaided eye coupled with the specific binding partner.
11. The method of claim 1 , wherein the labels visible to the unaided eye and the fluorescing elements are blocked with a blocking agent.
12. The method of claim 11 , wherein the blocking agent is bovine serum albumin.
13. The method of claim 1 , wherein the sample analysis device comprises at least two test lines to determine a presence of at least two targets.
14. The method of claim 1 , wherein the sample analysis device comprises a single test line to determine a presence of at least two targets.
15. The method of claim 1 , wherein a visible color of the label visible to the unaided eye is the same as a fluorescing color of the fluorescing element.
16. The method of claim 1 , wherein a visible color of the label visible to the unaided eye is different than a fluorescing color of the fluorescing element.
17. The method of claim 1 , wherein the sample analysis device is a lateral flow chromatographic test strip and further comprises:
a) an application zone for applying a sample to the sample analysis device;
b) a detection zone for detecting the analyte, wherein the detection zone is laterally downstream from the application zone.
18. The method of claim 1 , wherein the labels visible to an unaided eye and the plurality of fluorescing elements are coupled to the same specific binding partner for the target.
19. The method of claim 1 , wherein the at least one specific binding partner comprises a mixture of at the least one specific binding partner coupled to the plurality of labels visible to an unaided eye and the at least one specific binding partner coupled to the plurality of fluorescing elements.