The method detects by precipitation: when a soluble antigen (Ag) is brought in contact with the corresponding antibody, precipitation occurs, which may be visible with the naked eye or microscope.
Immunofixation identifies (antibodies) in a mixture in function of their specific electrophoretic mobility. For the identification antigens are used that are specific for the targeted antibody.
Specifically, immunofixation allows the detection of monoclonal antibodies representative of diseases such as myeloma or Waldenström macroglobulinemia.
Plasma or concentrated urine is deposited on a gel. With an electrical current the proteins are sorted in function of their size, after which antigens for each targeted type of immunoglobulin are deposited on the gel. Thus more or less narrow bands appear on the gel, marking the location of the various immunoglobulines.