Immunofluorescent detection of hepatitis B antigen in paraffin-embedded liver tissue.

Hepatitis B antigen (HBAg) has been demonstrated by the indirect immunofluorescent technique and by orcein staining in 20 liver biopsies fixed in Bouin's fixative and embedded in paraffin. The results were compared with those obtained previously by immunogluorescence on frozen sections of the same biopsies. Ten biopsies which were positive in frozen sections were also positive by immunofluorescence in parafin sections, whereas only six were positive by orcein staining. In orcein-stained sections, the cellular localization of HBAg was precisely in the same places as in the slides examined by immunogluorescence. The intessity of the fluorescence in paraffin sections was almost the same as in frozen sections. The localization of the antigen was histologically more precise in paraffin sections. Besides various advantages, indlucing aboidance of freezing aquipment and procedures, paraffin sections are more easy to handle and biopsies from distant hospitals can be processed. The advantages of the immunofluorescent test in comparison to orcein staining are its immunological specificity and higher sensitivity.