Advances in immunohistochemistry: impact on surgical pathology practice.

Over the past decade, the many advances in immunohistochemical techniques have revolutionized the field of immunohistochemistry. Most notable is discovery of the use of heat for antigen retrieval, which permits consistent and reliable demonstration of antigens in routine surgical pathology specimens despite variations in the duration of fixation and tissue processing schedules. As a result, immunohistochemical studies play an increasingly important role in surgical pathology, such as help in rendering a diagnosis in a crushed specimen, classification of tumors, prediction of the likely origin of a carcinoma, demonstration of micrometastases, provision of prognostic information, and demonstration of microorganisms. To serve such purposes, immunohistochemical stains must be performed at a high standard with consistent and reproducible results. The stains must be interpreted cautiously in the appropriate context, and potential pitfalls such as endogenous biotin activity must be recognized. The increased demand for immunohistochemical tests raises the issue of cost containment, which can be achieved through a number of ways, such as deletion of nonvalue-added tests, deletion of antibodies that no longer serve a purpose, replacement of the conventional positive control with a multitissue control mounted on the same slides of the test cases, various means of savings on antibodies, and continuing to use "expired" antibodies. To keep abreast of modem developments in the field in this era of information explosion, the internet can play an important role by providing updated information or database and a platform for rapid exchange of knowledge.