Abstract: The invention relates to methods of determining the presence or amount of an analyte in a sample suspected of containing the analyte, said method comprising the steps of: (a) bringing together in an aqueous medium to form a mixture: (i) the sample; (ii) at least one specific binder for the analyte; (iii) a first binding agent coupled to either (1) exogenous analyte or (2) the specific binder for the analyte; (iv) a support comprising a second binding agent; b) adding an activator to the mixture, wherein the activator binds the first binding agent and the second binding agent of the support to immobilize the first binding agent; c)determining the amount of the analyte in the sample by detecting the immobilized first binding agent, the presence or amount thereof being related to the presence or amount of the analyte in the sample.

Abstract: This invention pertains to methods to detect antibodies in a sample. The methods use an amount of antigen that is up to 1000, preferably 10-100 times the minimum amount antigen that can be reliably detected and that is less than the maximum expected amount of antibodies in the sample. An antigen:antibody complex is formed and becomes bound to a binding agent that does not bind free antigen. The free antigen is then detected as a measure of antibodies present in the sample.