Interpretation and quantification of immunostains

Despite the fact that immunohistochemistry is widely used in routine diagno stic work and is a very common part of scientific reports in pathology and cytology, its standardization still lags behind. Interpretation of immunost ains should be based on microanatomic distribution of the staining, proport ion of positively stained cells, staining intensity, if relevant, and cutof f levels. These parameters should be shown to be reasonably reproducible an d should be clearly defined in publications. Uniformity in the setting of t hresholds could probably benefit from interlaboratory control materials con taining defined amounts of the target antigen. Reliable and precise quantit ative immunohistochemistry requires the use of control materials containing defined amounts of the target antigen and processed alongside the specimen combined with automated computer-assisted microspectrophotometry. Applicat ion of these suggestions is hoped to improve standardization and to facilit ate communication in the field of immunohistochemistry.