Quality assurance issues in immunohistochemistry

Although immunohistochemistry has emerged as a major technique for tumor diagnosis, there is still a lack of interlaboratory standardization, leading to poor reproducibility of immunohistochemical stains. Much of the problem has to do with lack of quality control within each laboratory. This report discusses tissue fixation, epitope retrieval methods, controls, background staining, and interpretation of immunostains. Preventive measures and a quantitative immunohistochemical system for quality control are presented.