Patent ID: 7153681

Claim:
An assay device for detection of an analyte in a liquid sample, comprising: (a) a support; (b) a test line comprising a first specific binding reagent immobilized on the support; (c) a control line comprising a second specific binding reagent immobilized on the support; (d) a mobile reagent disposed in the device at a reagent position located upstream from the test line and the control line such that a liquid sample applied to the device transports the mobile reagent from the reagent along the support in a downstream direction through the positions of the test line and the control line, wherein the mobile reagent comprises a direct particulate label co-sensitized with a third specific binding reagent having specificity for the analyte, and a protein which is specifically bound by the second specific binding agent but does not bind to the first specific binding agent or otherwise participate in complex formation which would lead to capture of the mobile reagent in the test line, and wherein the first specific binding agent specifically binds to the analyte.