HBV diagnosis

Serological markers are commonly used as diagnostics and/or prognostic indicators of acute or chronic HBV infection. The most common marker of HBV infection is the presence of HBV surface antigen (HBsAg). HBV e antigen (HBeAg) is generally used as a secondary marker to indicate active HBV replication associated with progressive liver disease.

Variant strains of HBV can produce HBeAg that is not detectable in serum even when an active infection is present. Therefore, using this marker to monitor disease progression may be of limited utility. The ability to detect HBV DNA in serum has been shown to have prognostic value for the outcome of acute HBV infections. HBV DNA levels persisting for longer than eight weeks have been shown to be indicative of progression to chronic liver disease, while clearance of HBV DNA within two weeks of onset of symptoms is associated with complete recovery from acute hepatitis.

The efficacy of anti-viral therapy used to treat patients with HBV can also be assessed by serologic markers or by measurement of liver enzyme function. However, quantitative determination of viral DNA in serum or plasma is considered the most direct and reliable measurement of viral replication. A rapid and sustained drop in HBV DNA levels in patients receiving alpha-interferon therapy has been shown to be a predictive factor for a favourable treatment outcome. Therefore, a quantitative test for the measurement of HBV DNA is a valuable tool to be used in conjunction with other serological markers of HBV infection.