COMPARISON OF ENHANCED CHEMILUMINESCENCE AND MICROPARTICLE ENZYME-IMMUNOASSAY FOR THE MEASUREMENT OF HEPATITIS-B SURFACE ANTIBODY

Two commercially available immunoassays for the quantitative measureme nt of antibodies to hepatitis B surface antigen (HBsAg) were compared. The Amerlite enhanced chemiluminescence assay (ECL), which utilizes c apture antigen obtained from HBsAg-positive donors bound to microtitre wells, was compared with the Abbott Laboratories microparticle enzyme immunoassay (IMx), which uses a recombinant antigen coated on to micr oparticle carriers. A total of 310 specimens, 116 from naturally infec ted patients (group A), 93 from patients vaccinated with a human plasm a-derived vaccine (group B) and 101 patients vaccinated with a recombi nant vaccine (group C), were tested in both assays undiluted and dilut ed 1:11. Samples that showed discordant results were also tested in a conventional quantitative enzyme immunoassay (Sorin). The results show significant differences in the level of anti-HBsAg in patient sera us ing the two technologies. In general, IMx gave significantly higher va lues than ECL for all three patient categories tested. These differenc es may lead to conflicting reports being issued by laboratories who ch ange their assay system or when a sample from one patient is tested by different laboratories using different assays.