Analytical assay method
First Claim
1. A method for determining the presence of an analyte in a sample fluid comprising(a) distributing a sample of fluid across the surface of a multilayer assay element which comprises:
- i. a light-blocking layer which is permeable to said fluid; and
ii. a reagent layer comprising an immobilized specific binding partner for said analyte and a conjugate of a label bound to a moiety which binds to said binding partner, wherein said analyte and said specific binding partner are each a member of an antigen-antibody binding pair;
(b) obtaining a readout signal after step (a) by irradiating said reagent layer with electromagnetic radiation which is in the absorption region of said label;
(c) taking the ratio of said readout signal from step (b) to a readout signal obtained by irradiating said reagent layer with the same electromagnetic radiation used in step (b) prior to distributing said fluid sample in step (a); and
(d) comparing said ratio with like ratios obtained for known concentrations of said analyte to determine the concentration of analyte in said sample.
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Abstract
A method for determining the amount of an analyte in a sample fluid utilizes a multilayer assay element which comprises at least one reagent layer and a light-blocking layer. The assay method includes the steps of optically reading a signal producing species, e.g. a fluorescent label, a first time before the sample fluid is applied to the assay element and a second time, at the same wavelength and in the same location within the assay element, after the sample fluid has been applied to the assay element and the sample analyte has interacted with the reagent(s) present in the assay element. The ratio of the two signals is taken and compared with that for known amounts of the analyte to determine the amount of analyte in the sample fluid.
23 Citations
7 Claims
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1. A method for determining the presence of an analyte in a sample fluid comprising
(a) distributing a sample of fluid across the surface of a multilayer assay element which comprises: -
i. a light-blocking layer which is permeable to said fluid; and ii. a reagent layer comprising an immobilized specific binding partner for said analyte and a conjugate of a label bound to a moiety which binds to said binding partner, wherein said analyte and said specific binding partner are each a member of an antigen-antibody binding pair; (b) obtaining a readout signal after step (a) by irradiating said reagent layer with electromagnetic radiation which is in the absorption region of said label; (c) taking the ratio of said readout signal from step (b) to a readout signal obtained by irradiating said reagent layer with the same electromagnetic radiation used in step (b) prior to distributing said fluid sample in step (a); and (d) comparing said ratio with like ratios obtained for known concentrations of said analyte to determine the concentration of analyte in said sample. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification