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Hepatitis B PCR
Medical expert of the article
HBV in the material is normally absent.
Approximately 5-10% of cases of cirrhosis and other chronic liver diseases are caused by chronic viral hepatitis B. The markers of the activity of such diseases are HB e Ag and DNA of the virus in serum.
PCR allows to determine HBV DNA both qualitatively and quantitatively in the test material (blood, punctate liver). Qualitative determination of HBV in the material allows to confirm the presence of the virus in the patient's body and thereby establishes the pathogenesis of the disease. The quantitative method for determining the content of HBV DNA in the test material provides important information about the intensity of the disease, the effectiveness of treatment and the development of resistance to antiviral drugs. For the diagnosis of viral hepatitis using the PCR method in the serum, test systems are currently used, their sensitivity is 50-100 copies in the sample, which makes it possible to detect the virus at a concentration of 5 × 10 3 -10 4 copies / ml. PCR in viral HBV is certainly necessary for judging about viral replication. Viral DNA in serum is detected in 50% of patients in the absence of HB e Ag. The material for detecting HBV DNA can be serum, as well as lymphocytes and hepatobiobaptam. Evaluation of the results of the study on HBV DNA is largely similar to that described for viral hepatitis C.
Detection of HBV DNA in the material by PCR is necessary in the following cases:
- resolution of questionable results of serological studies;
- the detection of the acute stage of the disease in comparison with the transferred infection or contact;
- monitoring the effectiveness of antiviral treatment.
There is a relationship between the outcome of acute viral hepatitis B and the concentration of HBV DNA in the patient's blood. With a low level of viremia (less than 0.5 pg / μl), the process of chronic infection is close to zero, at a concentration of HBV DNA from 0.5 to 2 pg / ml, the process is chronically occurring in 25-30% of patients, and with a high level of viremia (more 2 pg / ml) acute viral hepatitis B most often becomes chronic.
Indications for treatment of chronic hepatitis B should be considered interferon alpha presence of markers of active viral replication (detection HB s Ag, HB e Ag and HBV DNA in serum during the preceding 6 months). The criterion for evaluating the effectiveness of treatment is the disappearance of HB e Ag and HBV DNA in the blood, which is usually accompanied by normalization of transaminase activity and long-term remission of the disease.