Abstract: An immunoassay method including reacting a sample from a patient with a bispecific antibody, wherein the bispecific antibody includes one antibody specific for a compound to be detected and a second antibody specific for a compound foreign to said patient sample, and subsequently reacting the patient sample with a polymer probe, wherein the polymer probe includes a compound recognized by the second antibody in the bispecific antibody complex and further includes at least two detectable signals; the bispecific antibody; and the polymer probe of the immunoassay method are disclosed.