Enzyme immunohistochemistry: technical aspects.

The enzyme immunohistochemical techniques developed during the past decade have contributed greatly to our understanding of disease processes and have become an essential tool in the evaluation of many disease states. The availability of these techniques permits the visual localization of tissue antigens in permanent preparation with the potential for visualization of adjacent tissue morphology. This paper outlines the theoretical principles underlying immunohistochemical techniques, the new technical developments and pitfalls of currently available techniques, characterization of nonhazardous chromogens, and quality control for these procedures.