Preparation of immunoassay device, useful for detecting antigens, particularly pregnancy hormones, includes incorporation of concurrent antibody to ensure selectivity for a single antigen

摘要

Preparing an immunoassay device used to detect antigens (1,2) in a test liquid, is new. Preparing an immunoassay device used to detect antigens (1,2) in a test liquid comprises: (a) providing a porous carrier (10); (b) applying a probe antibody (3), labeled with an optically detectable dye (5), to a start zone (S) of (10), where (3) can bind to both (1) and (2) and is fixed to (S) in the dry state but in the wet state can migrate through (10) in the flow direction; and (c) permanently immobilizing a detection antibody (6) in a detection zone (D), where (6) can bind to (1) and (3) in a sandwich reaction. The new features are that (6) is also reactive with (2) and (3) in a sandwich reaction and the process includes applying at least one concurrent antibody (cAb) to (S) (where it is fixed/mobile as for (3)). cAb is selected so that it can bind to (1) or (2), alternatively and with higher selectivity than (3) or (6), according to whether the assay is designed to detect (1) or (2). Independent claims are also included for: (1) detecting (1) or (2) in a test liquid using an immunoassay device prepared by the new method; and (2) immunoassay device prepared by the new method.