Immunochemistry is a branch of chemistry that involves the study of the components and functions of the immune system such as the nature and interactions of antigen-antibody. Immunochemistry involves the use of simple, rapid, robust yet sensitive automated methods for routine analyses in clinical laboratories.Immunohistochemistry (IHC) is an important application of monoclonal as well as polyclonal antibodies to determine the tissue distribution of an antigen of interest in health and disease. IHC is widely used for diagnosis of cancers; specific tumor antigens are expressed de novo or up-regulated in certain cancers.IHC Tests (ImmunoHistoChemistry) Save as Favorite. IHC, or ImmunoHistoChemistry, is a special staining process performed on fresh or frozen breast cancer tissue removed during biopsy. IHC is used to show whether or not the cancer cells have HER2 receptors and/or hormone receptors on their surface.