Comparison of Three Luminescent Immunoassays for Hepatitis B Virus Surface Antigen Quantification during the Natural History of Chronic Hepatitis B Virus Infection

Abstract

bHepatitis B surface antigen (HBsAg) quantification has garnered attention because of its high predictive value in determining treatment responses. The HBsAg quantification assays, such as Architect and Elecsys, are commercially available, and more assays are in development. We aimed to compare the results of the Architect and Elecsys assays with those of a new assay, WTultra. The WTultra HBsAg assay is a sandwich chemiluminescent microplate enzyme immunoassay and provides an alternative choice which is more cost-effective and potentially applicable in developing or resource-constrained countries and areas. A total of 411 serum samples were collected from patients during various phases of chronic hepatitis B (CHB) infection. The samples were assessed using the three assays, and the results were compared and analyzed. Since the discovery of the hepatitis B surface antigen (HBsAg) by Blumberg in 1965, HBsAg detection has been the leading hallmark for diagnosing an HBV infection (2). HBsAg persistence longer than 6 months is the key diagnostic criterion for chronic hepatitis B (CHB) infection (3). HBsAg seroclearance reflects the immunological control of the infection and confers an excellent prognosis in the absence of preexisting cirrhosis or concurrent infections with other viruses (3-5).HBsAg quantification assays have been available for several years; however, the clinical application of HBsAg quantification has recently drawn attention. Several studies initially demonstrated an association between the levels of HBsAg and the levels of covalently closed circular (ccc) DNA, the template for viral replication inside the nuclei of hepatocytes (6, 7). Subsequently, serum HBsAg levels were hypothesized to be a marker of an immunological response to therapy, independent of the virological response detected from HBV DNA levels. Recently, evidence has suggested that the HBsAg levels change during the natural course of chronic HBV infection (8, 9), and a rapid decline in HBsAg levels indicates a strong response to therapy, regardless of the treatment approach. Monitoring HBsAg levels can help identify nonresponders to therapy (peginterferon [PEG-IFN] or nucleoside analogues) and determine the best management strategy for many patients (10-15).Currently, the most widely used assay for HBsAg quantification is the Architect assay (16), followed by the Elecsys platform. These assays are fully automatic, based on microparticle and automated large-scale instruments. The WTultra HBsAg assay is a novel chemiluminescent microplate enzyme immunoassay (CLEIA) that requires manual dilution and operation, and the assay cost is much lower, which is a potential requirement in some developing countries and areas. The HBsAg level varies greatly during the natural phases of HBV infection, and the Architect assay has been proven to be reliable in various scenarios; however, other assays have not been fully evaluated in each natural phase, highly limiting their clinical usage. The aim of this study was to compare these three assays for ...