Abstract: A membrane holder for use with a diagnostic device comprises an interlocking first plate and a second plate. The first plate has a top surface flush with a hole, while the bottom surface defines a raised ring, a projection in one corner and an orifice in another corner. The second plate has a top surface having a recess for accepting a membrane, within which is a hole and ribs emanating outwardly to a raised circular rib from which a recessed ring emmanates. The recessed ring of the second plate is adapted to accept the raised ring of the first plate. The top surface of the second plate further has a projection in one corner and an orifice in another corner which mate with those in the first plate. The bottom surface of the second plate has a member to guide liquid away from the membrane. To assemble, a membrane is placed in the recess on the top surface of the second plate.

Abstract: A diagnostic device for conducting enzymatic and chromogenic assays, the device having a plurality of test conduits therein, individual assay membrane assemblies disposed in each of the conduits, barrier walls extending between adjoining conduits to proximate a bottom wall of the device, to discourage liquid passing from one of the conduits to an adjoining conduit.