Abstract: In a diagnostic apparatus system, a one piece porous substrate is provided in a container. The substrate serves both to extract an antigen in or on a top layer thereof with the remainder of the substrate serving as a reservoir. The pores in the top surface of the substrate are microscopic for entrapment of microspheres carrying antibodies. A target antigen in a test sample attaches to the antibodies when the test sample is poured through the top layer. The pores in all but the top layer of the substrate have a much greater pore size to comprise tile reservoir portion of the substrate.

Abstract: In a diagnostic apparatus system, a one piece porous substrate is located in a container. The substrate serves both to extract an antigen in or on a top layer with the remainder of the substrate serving as a reservoir. The pores in the top surface of the substrate are microscopic for entrapment of microspheres carrying antibodies. A target antigen in a test sample attaches to the antibodies when the test sample is poured through the top layer. The pores in all but the top layer of the substrate have a much greater pore size to define the reservoir portion of the substrate. The invention also includes a method of casting a microporous matrix in surfaces of a plurality of macroporous slugs.