| abstract |
A lateral flow device having a porous reaction zone (2, 3) in communication with a porous filter zone (4). The reaction zone (2, 3) contains (i) analyte-specific label and (ii) a particulate carrier having analyte-specific capture reagent immobilised thereon. The filter zone (4) has a smaller pore size than the reaction zone (2, 3). Label not bound to the particulate carrier can thus enter the filter zone (4), unlike label that is bound to the carrier. After applying a sample, lateral flow brings analyte into contact with label and particulate carrier within the reaction zone (2, 3), to form a complex. Free label does not bind to the particulate carrier. During flow from the reaction zone (2, 3) to the filter zone (4), free label migrates into the filter zone (4), whereas particle-analyte-label complex is captured at its entrance (6). This avoids the need to use immobilised antibody to capture an analyte-label complex. |