A device is disclosed for conducting an assay method. The device comprises a housing, means enclosed in the housing for capturing a member of a specific binding pair in a zone and for allowing liquid to be transported by capillary action away from the zone, one or more self-contained liquid reagents enclosed in the housing for conducting an assay method for the determination of an analyte in the sample, and means in the housing for introducing the sample into the device. Preferably, the self-contained reagents are liquid reagents which are contained in a breakable container. The device of the invention finds use in assay methods for the determination of an analyte in a sample suspected of containing the analyte. Kits for conducting an assay method are also disclosed.