Rodent immunohistochemistry: pitfalls and troubleshooting

Immunohistochemistry (IHC) is a common adjunct in pathology for morphologic diagnosis, research pathology, and studying the pathogenesis of the disease. Proper technique and interpretation of an immunohistochemistry assay is of utmost importance. A variety of problems, including the presence of artifacts (nonspecific background or other staining problems) and the differentiation between nonspecific and specific staining, commonly occur. It is essential that antibody quality and IHC technique be optimized. We review the histologic patterns of specific and nonspecific staining after using IHC techniques, as well as basic troubleshooting procedures, and provide some examples of nonspecific staining and other artifacts especially in formalin-fixed, paraffin-embedded tissues (FFPE) of mice.