WO2004081529A3 - Assay device and method - Google Patents

Abstract

The present invention provides a test device for detecting the presence or absence of a selected analyte in a liquid sample. The test device includes a reagent member comprising a body, a first labeled binding reagent specific for a first binding site of said analyte and a second labeled binding reagent specific for a second binding site of said analyte, each conjugated to the same label, wherein said first specific binding site and said second binding site are different; wherein said reagent body is adapted to retain said first and second labeled specific binding reagents when said body and said first and second labeled binding reagents are dry, and to release said first and second labeled specific binding reagents when said body and said first and second labeled specific binding reagents are moist, and wherein said first and second labeled specific binding reagents are capable of forming a first labeled complex with said analyte, said complex comprising said analyte conjugated to two conjugated labels, the first conjugation with said first specific binding reagent and the second conjugation with said second specific binding reagent; a porous carrier; and a detection zone comprising a first porous barrier having an average pore size larger than the diameter of the larger diameter of the label, but smaller than the diameter of said first labeled complex; wherein said reagent member, porous carrier, and detection zone are arranged so that a fluid applied to said test device would travel sequentially from said reagent member to said porous carrier and to said detection zone. The test device is typically dry before use and moist during use.