Detection of delta infection using reagents obtained from the serum of patients infected with HBV

A microtitre solid-phase radioimmunoassay (SPRIA) was developed for the detection of delta antigen (delta Ag) and antibody (anti-delta) using sera from subjects who had been infected with this agent as the source of antigen and antibody. The assay was compared with reference tests, which use delta antigen extracted from liver tissue obtained at autopsy, and found to be equally sensitive and specific.