A process for determining the presence of an antigen or antibody in a sample wherein said antigen or antibody exists in the form of an immune complex which comprises:

A. contacting the immune complex originating from the sample suspected of containing immune complex with a dissociating buffer whereby said immune complex, if present, is dissociated into antigen and antibody;
B. contacting a solid support which binds proteins with said dissociating buffer suspected of containing antigen or antibody and removing said buffer;
C. washing said solid support;
D. adding protein to fill unoccupied sites on said solid support;
E. adding radioactively labeled or enzyme labeled antibody or antigen to said support, said labeled antibody or antigen corresponding to antigen or antibody on said solid support, incubating the resultant mass and washing the same;
F. measuring the radioactivity or enzymatic activity associated with the solid support.