WO2004106929A3 - Assay method - Google Patents

Abstract

The present invention provides a method for assaying for an analyte in a sample, said method comprising: applying to a porous membrane to which optionally is bound a first specific binding partner for said analyte: (i) said sample; (ii) a water-binding polymer in aqueous solution; and (iii) one or both of a second, optionally labelled specific binding partner for said analyte in aqueous solution or dispersion and a labelled ligand for a said specific binding partner; flushing said membrane; and measuring a signal from or induced by a labelled material retained on the surface of said membrane whereby to generate an indication of the content of said analyte in said sample; with the provisos that the porosity of said membrane is such that, in the absence of any said first specific binding partner bound thereto, said second specific binding partner (where used) is able to be flushed therethrough but conjugates of said second specific binding partner and said labelled ligand (where used) are not able to be flushed therethrough, that at least one of said first and second specific binding partners is used, that at least one of a said labelled second specific binding partner and a said labelled ligand is used, and that where no first specific binding partner is used then both a said second specific binding partner and a labelled ligand are used.