Demonstration of hepatitis B-surface antigen in liver biopsies. A comparative investigation of immunoperoxidase and orcein staining on identical sections of formalin fixed, paraffin embedded tissue.

Staining of 1000 consecutive liver biopsies with orcein showed positive reaction in the cytoplasm of ground-glass hepatocytes in 18 of the biopsies. On new sections of the 18 orcein positive biopsies immunoperoxidase staining was performed in order to demonstrate hepatitis B-surface antigen (HBsAg). After destaining the same sections were stained with orcein. All biopsies showing positive orcein staining showed positive immunoperoxidase reaction. The number of positive cells was in biopsies with less than 20 positive cells per mm2 biopsy larger using the immumoperoxidase staining than with orcein staining. Further the staining contrast was more pronounced. Immunoperoxidase staining thus seems more sensitive than orcein staining for demonstrating HBsAg in liver tissues. Orcein stains HBsAg in liver tissue even though the antigen determinants are blocked by antibodies.