Information: Orcein Solution may be used in histology procedures for the visualization of Hepatitis B surface Antigen (HBsAg), elastic fibers, and copper associated proteins. HBsAg appears as irregular shaped aggregates in the cytoplasmic region of the cells. This reagent may be used on formalin-fixed, paraffin-embedded or frozen sections. HBsAg: Dark Brown/Purple Elastic Fibers: Dark Brown/Purple Copper Assoc. Proteins: Dark Purple Background: Light Reddish/Purple