Immunohistochemistry: An overview

Over the last two decades, immnohistochemistry has had an immense impact on the practice of diagnostic pathology. It relies on the binding of immunoglobulins to antigens present in tissues. The antigen-antibody reaction is revealed by an enzymatic reaction or the colour emission of a fluorochrome. Due to the specificity and sensitivity of this reaction, immunohistochemistry is an excellent alternative to more complex, expensive and time-consuming other laboratory procedures. If used carefully, it can be an excellent diagnostic tool. But unfortunately, because of lack of standardizations or other various pitfalls, many times false positive or false negative results can be obtained. Hence, the results obtained with immunohistochemistry should always be correlated with the clinical history and other clinicopathological data available before making a final diagnosis. In this article, I have tried to focus on the basics of the immunohistochemistry and attempted to throw a light on the indications, advantages, complexities and limitations and the prognostic significance of this diagnostic tool.