The present invention provides a system and method for detecting antigens captured on an antibody array. The method comprises the following steps of providing the antibody array having at least two antibodies, contacting the antibody array with a sample containing at least one antigen that may be captured by the antibodies disposed on the antibody array, and detecting the at least one antigen captured by the antibody array with a detecting agent that specifically binds to the antigen-bound antibodies on the antibody array, thereby the at least one antigen captured by the antibody array can be detected independent of the structures of the antigens. In a preferred embodiment, Clq is used as the detecting agent to detect antigen-bound antibodies.