Preparation of enzyme immunoassay kit for the detection of hepatitis B surface antigen

An attempt was made to prepare enzyme immunoassay (EIA) kit for the detection of hepatitis B surface antigen (HBsAg). The diagnostic reagents were prepared by the 'sandwich" principle in which polystyrene microtiter plates were used. Two-step glutaraldehyde coupling procedure was used for the preparation of antibody-peroxidase (horseradish) conjugate. Purified anti-HBs IgG fraction of guinea pig antisera was used for coating plates and for antibody-enzyme conjugate preparation. This method had been compared with Ausria II-125 (RIA, Abbott Lab.) in 423 government employees. Among 80 (18.9%) positive results six were inconsistent reactions by Ausria II-125. Only one of the six positive specimens was repeatedly positive and was confirmed by Auszyme II (EIA, Abbott Lab.). 14 out of the 343 (81.1%) negative results were positive reactions detected by Ausria II-125. A half of them was still negative detected by Auszyme II. The lowest detectable dose of our EIA, in which the Hepatitis Sensitivity Panel-5 (Abbott Lab.) was used and incubation period was set for 2 hr., was 3.2 ng/ml for ad subtype of HBsAg. While that of Auszyme II was 0.93 ng/ml.