Extension of the dynamic detection range of assay devices
First Claim
1. A flow-through assay device for detecting the presence or quantity of an analyte residing in a test sample, said flow-through assay device comprising a porous membrane in communication with optical detection probes conjugated with a first antibody specific for the analyte, said porous membrane defining:
- a competitive zone that contains a second antibody immobilized on said porous membrane that is complexed to an antigen containing an optically detectable substance prior to the application of a test sample to the device, said antigen being identical to or an analog of the analyte and said optically detectable substance being capable of producing a competitive signal when contained within said competitive zone; and
a detection zone within which a third antibody is immobilized that is configured to bind to complexes formed between the analyte and said conjugated optical detection probes to produce a first detection signal, said third antibody also being configured to bind to said antigen from said competitive zone to produce a second detection signal, wherein the amount of the analyte within the test sample is determined from said competitive signal, and at least one of said first detection signal and said second detection signal.
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Abstract
A flow-through assay device for detecting the presence or quantity of an analyte residing in a test sample is provided. The device utilizes multiple detection zones, one of which is premised on “competitive” binding of the analyte and the other is premised on “sandwich” binding of the analyte. The present inventors believe that the combination of these zones may enable the detection of an analyte over extended concentration ranges.
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Citations
9 Claims
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1. A flow-through assay device for detecting the presence or quantity of an analyte residing in a test sample, said flow-through assay device comprising a porous membrane in communication with optical detection probes conjugated with a first antibody specific for the analyte, said porous membrane defining:
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a competitive zone that contains a second antibody immobilized on said porous membrane that is complexed to an antigen containing an optically detectable substance prior to the application of a test sample to the device, said antigen being identical to or an analog of the analyte and said optically detectable substance being capable of producing a competitive signal when contained within said competitive zone; and a detection zone within which a third antibody is immobilized that is configured to bind to complexes formed between the analyte and said conjugated optical detection probes to produce a first detection signal, said third antibody also being configured to bind to said antigen from said competitive zone to produce a second detection signal, wherein the amount of the analyte within the test sample is determined from said competitive signal, and at least one of said first detection signal and said second detection signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification