The use of paraffin-processed tissue and the immunoperoxidase technique in the diagnosis of bullous diseases, lupus erythematosus and vasculitis.

Twenty-two skin biopsies have been split and each half examined either by the immunoperoxidase technique on paraffin-fixed tissue or by both immunoperoxidase (IP) and immunofluorescence (IF) technique on snap-frozen tissue. All twenty-two specimens gave positive results by frozen IF techniques, nineteen out of twenty-two (86%) were positive by frozen IP techniques and sixteen out of twenty-two (72%) were positive by IP on paraffin-fixed material. If retrospective immunopathology is required on a specimen and only paraffin-fixed material is available a positive result may be expected in the majority of cases.