Immunoassays

Immunoassays are based on the principles that specific antigens will stimulate very specific and unique immune responses and that the proteins produced by the immune response, called antibodies, can be used to signal the presence of a target compound in a sample. The principle of an indirect EIA for antibody is when an antibody in the specimen is bound by a "capture antigen" which has been attached to a solid surface. The bound antibody is detected by binding an added enzyme conjugated anti- human antibody. The bound enzyme labeled antibody is detected by its ability to break down its substrate to a coloured product. Although enzyme immunoassays can be set up in several different formats the indirect method is the most appropriate for the detection of total specific antibody.