Direct immunofluorescence of oral mucosal biopsies: a comparison of fresh-frozen tissue and formalin-fixed, paraffin-embedded tissue.

The diagnosis of some oral mucosal diseases can be facilitated by the use of direct immunofluorescence. Fresh frozen tissue is preferred when using this technique, however frequently the material received by the histopathology laboratory has been fixed in formalin. Enzyme digestion of tissue sections glued to glass slides prior to incubation with antibodies was shown in this study to give comparable results with direct immunofluorescence on fresh frozen tissue and can be used for diagnostic purposes when fresh frozen tissue is unavailable or not representative of the disease process.