Assessment of antigen damage in immunohistochemistry. The vimentin internal control.

Monitoring of the quality of antigen preservation and the uniformity of tissue fixation in paraffin-embedded, formaldehyde-fixed tissues is facilitated by the routine use of an antibody to an epitope of vimentin that is partially susceptible to formaldehyde fixation. Other diagnostically useful molecules often show fixation- or processing-induced alterations that parallel those of the vimentin epitope. Thus, the use of vimentin as an internal control, or reporter molecule, and its extrapolation to other antigens allow for better interpretation of results, improved selection of fields optimal for diagnostic immunohistochemistry, and more rational application of compensatory procedures, such as protease digestion.