title: Enzyme potentiated radioimmunoassay (EPRIA): a sensitive third-generation test for the detection of hepatitis B surface antigen.
abstract: A sensitive, specific immunoassay for detection of hepatitis B surface antigen (HBsAg) is described. The assay combined enzyme-linked immunosorbent assay and solid-phase radioimmunoassay and is termed enzyme potentiated radioimmunoassay (EPRIA). HBsAg was quantitated by enzymatic conversion of L[14C]glutamic acid to 14CO2 and gamma-aminobutyric acid by glutamate decarboxylase (GDC) conjugated wih goat anti-HGs IgG. Conjugation of IgG and GDC was by a thiol-disulfide bond exchange reaction after reacting N-succinimidyl 3-(2-pyridyldithio) propionate (SPDP) with each reagent. A positive/negative ratio of 2.2 was established as significant by examination of 40 normal sera negative for HBsAg. This value was the mean cpm plus 3 standard deviations. By an identical statistical analysis of sensitivity, EPRIA was found to be approximately 100-fold more sensitive than Ausria II (Abbott Laboratories, North Chicago, IL).
mesh_terms: D000818:Animals; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes; D005968:Glutamate Decarboxylase; D006041:Goats; D006168:Guinea Pigs; D006509:Hepatitis B / Q000175:diagnosis; D006514:Hepatitis B Surface Antigens; D006801:Humans; D006863:Hydrogen-Ion Concentration; D002679:Pan troglodytes; D011422:Propionates; D011863:Radioimmunoassay; D013388:Succinimides; D013696:Temperature; D013995:Time
chemical_list: D000939:Epitopes; D006514:Hepatitis B Surface Antigens; D011422:Propionates; D013388:Succinimides; C021749:N-succinimidyl propionate; D005968:Glutamate Decarboxylase