ABSTRACT
HBVcccDNA is the first template for HBV to replicate in hepatocytes and the key factor to HBV to continous infect, which can directly reflect HBV′s infections state and replication.The examination of HBVcccDNA is an effective index to evaluate anti-HBV drugs and an objective index to judge wheter HBV infects extrahepatic tissue. cccDNA found in the serum is an important sign of hepatocyte damage at an early stage. There are nested PCR, selective PCR, Southern imprinted hydridization etc.The methods of qualitative detection include real-time PT-PCR, competitive PCR and intruder detection. Currently, there are some deficiencies existing in the clinical method and the examination system of HBVcccDNA has not yet been formed.Further research and exploration are need to be done in order to provide reliable reference for clinical diagnosis and treatment. The level of HBVRNA in serum potentially reflect cccDNA′s existence and transcription in patient′s liver cells.