Real Time PCR Usage in the Quantification of Hepatitis B Virus DNA-Clinical Applications in Disease Management
Simultaneous quantification and detection of Hepatitis B virus (HBV) DNA plays significant role in diagnosing and monitoring infection related to HBV as well as assessing therapeutic response. Variability among HBV genotypes and the huge range of clinical HBV DNA levels presents challenges for PCR-based amplification techniques. High sensitivity, wide linear range, good reproducibility, and genotype inclusivity, combined with a small sample volume requirement and low cost, make this novel quantitative HBV Real-Time PCR assay particularly well suited for application to large clinical and epidemiological studies. Serum DNA levels are a prognostic factor, and contribute to define the phase of chronic hepatitis B (CHB) infection, the treatment indication, and allow an assessment of the efficacy of antiviral therapy. High levels of HBV DNA are an independent risk factor for cirrhosis and hepatocellular carcinoma HCC in Asia. Recent advances in antiviral therapy, based on the development of new and more powerful nucleotide analogues, have dramatically improved chronic hepatitis B management, including the prevention of allograft reinfection in those patients undergoing liver transplantation for HBV related disease. Advances in the molecular diagnosis of drug resistance using highly sensitive methodologies such as DNA Amplification by PCR can further detect upcoming viral resistance at an early stage when the variant represents only a minor fraction of the total viral population. Such new tools are especially relevant for patients at high risk for disease progression or acute exacerbation.