Diagnosis

Serologic testing of HBV involves a panel of several HBV-specific markers: HBV surface antigen (HBsAg), HBV core antigen (HBcAg) and HBV “e” antigen (HBeAg). These markers help distinguish whether a patient is susceptible to primary infection, immune as a result of a resolved infection, immune as a result of vaccination, acutely infected, or chronically infected. During acute infection, the appearance of virologic markers develop in a typical pattern. The first serologic marker to appear within 1-12 weeks of an acute infection is HBsAg, along with pre-S1 and pre-S2 antigens. Then, HBeAg becomes detectable which indicates that a person is highly infectious and clinical symptoms begin to develop. IgM antibody to HBcAg (anti-HBc) appears next and remains present for up to 4 months, after which only IgG antibody to HBcAg remains and persists indefinitely. Anti-HBe appears after anti-HBc and its presence correlates to a decreased infectivity. Acute hepatitis patients who maintain a constant serum HBsAg concentration or whose serum HBeAg persists for 8-10 weeks after symptoms have resolved, are at risk of developing chronic liver disease.

Type of HBV assays include:

Anti-HBc, IgM or Total

A positive anti-HBc IgM indicates a recent, acute infection (within the past 6 months). A positive anti-HBc Total is a non-specific assay used to detect acute, chronic, or resolved HBV infection. It may be used in pre-vaccination testing to determine previous exposure to an HBV infection, but it is not a marker of immunity.

HBsAg

Used to screen for and detect HBV infections, either recent or chronic. HBsAg is the earliest indicator of acute Hepatitis B and frequently identifies infected people before symptoms appear. HBsAg is the most widely used diagnostic and blood screening Hepatitis B test worldwide.

Anti-HBs

Used to determine immunity status. Used to detect previous exposure to HBV or to establish vaccination status. Subtypes adw, ady, and adr are each found in different geographic regions of the world. In Japan, China, and Southeast Asia, the r determinant predominates and in Europe, the US, Africa, India, Australia, and Oceania, the w determinant predominates. The y determinant is found in Africa and in Australia aborigines. (WHO, 2014)

HBeAg

A marker of a high degree of infectivity as it correlates with a high level of viral replication. Primarily used to monitor the effectiveness of treatment for chronic sufferers. However, some strains of HBV do not make “e” antigen, especially those found in the Middle East and Asia.

Anti-HBe

Used to diagnose and monitor the treatment of a chronic infection. Its presence suggests a low viral titer and a low degree of infectivity in persons with a chronic infection.