Abstract: The invention includes assay cassettes that can be employed during rapid flow-through binding assays. The assay cassettes can be disposable units suitable for one-time use and readily assembled to include a filter membrane carried between an upper plate and a lower plate. A pattern of channels can extend through the top plate to allow a fluid sample to be applied through the top plate and onto the filter. The bottom plate can include a plurality of channels that are aligned with the channel of the top plate and which will allow a negative pressure to be applied to the underside of the filter membrane to draw the sample through the filter. In one embodiment, the cassette includes a frangible section that allows the cassette to be divided into a first and second component.