Amplification immunoassay for the determination of hepatitis B surface antigen.

A sensitive sandwich immunoassay for the determination of Hepatitis B surface antigen (HBs) was developed, using a cascade system of Limulus amebocyte lysate as a signal amplification system. Lipopolysaccharide (LPS) was conjugated to anti-HBs antibody. Anti-HBs antibody was adsorbed to polystyrene beads. First, HBs were reacted to solid phase anti-HBs antibody (a-HBs). After the reaction, the beads were rinsed, and were then reacted with a-HBs-LPS. Then, LPS activity specifically bound to the beads was measured. HBs could be measured in the range of 10(-10)-10(-12) g/mL.