Hepatitis B Virus Core (HBc) Total Antibody EIA
ORTHO® HBc ELISA Test System is a qualitative enzyme-linked immunosorbent assay for the detection of total antibody to hepatitis B virus core antigen (anti-HBc) in human serum or plasma indicated for the screening of blood and blood products intended for transfusion and as an aid in the diagnosis of ongoing or previous hepatitis B virus infection. This test is not intended for use on samples of cord blood.
About Hepatitis B
A variety of serologic markers appear following infection with hepatitis B virus (HBV). The first marker to appear is usually hepatitis B surface antigen (HBsAg). Antibodies to hepatitis B core antigen (anti-HBc) appear next and remain detectable following the clearance of HBsAg and into convalescence. Antibodies to hepatitis B surface antigen (anti-HBs) generally appear a few weeks after the clearance of HBsAg.
The determination of anti-HBc in serum and plasma may be used as an aid to monitor the progress of HBV infection. Anti-HBc appears in virtually all individuals infected with HBV and is an accurate serological marker of recent and past infection.1,2 During the acute phase of HBV infection, anti-HBc appears shortly after the appearance of HBsAg and persists following HBsAg clearance.3 In those cases where HBsAg has cleared and the appearance of anti-HBs is delayed, anti-HBc may be the only serological marker of recent HBV infection.4 Anti-HBc is found in virtually all patients with chronic hepatitis B.5
Enzyme-linked immunosorbent assay (ELISA) procedures provide a means for routinely detecting antibodies to specific antigens.6,7 The detection of total anti-HBc has value considering the association of such antibodies with HBV infections.
The assay procedure is a three-stage test carried out in a microwell coated with recombinant-derived hepatitis B core antigen (rHBcAg). The recombinant antigen used in this assay is prepared under U.S. License by Novartis Vaccines and Diagnostics, Inc. under a shared manufacturing arrangement. The recombinant antigen is produced in Escherichia coli.
In the first stage, a test specimen is placed directly in the test well containing specimen diluent and incubated for a specified length of time. If anti-HBc is present in the specimen, antigen-antibody complexes will form on the microwell surface. If anti-HBc is not present, complexes will not form and the unbound serum or plasma proteins will be removed in the washing step.
In the second stage, antibody conjugate is added to the test well. The antibody conjugate is a mixture of murine monoclonal antibodies specific for human IgG and IgM. The conjugate will bind specifically to the antibody portion of the antigen-antibody complexes. If antigen-antibody complexes are not present, the unbound conjugate will be removed by washing.
In the third stage, an enzyme detection system composed of o-phenylenediamine (OPD) and hydrogen peroxide is added to the test well. If bound conjugate is present, the OPD will be oxidized, resulting in a colored end-product. Sulfuric acid is then added to stop the reaction. The color intensity depends on the amount of bound conjugate and therefore is a function of the concentration of anti-HBc present in the specimen. The color intensity is measured with a microwell reader. Test performed by VRL Eurofins, 6933 S. Revere Parkway, Centennial, CO 80112. This test has been cleared or approved for diagnostic use by the U.S. Food and Drug Administration. See package insert for more information.