Introduction: Viral DNS and/or RNS contain the genetic information necessary for its own reproduction and the synthesis of viral proteins. During this decade the new molecular biological methods made it possible to identify the nucleotide sequences of virus undetectable with traditional methods and to investigate the genetic background of their highly variable viral pathogenecities.
Aims: In the present study the author introduces the gene diagnostic methods based on polymerase chain reaction, nucleotide sequence analysis and hybridization, which have been carried out to the adequate diagnosis, to the monitoring of the antiviral therapy of chronic viral hepatitis B and C.
Methods: Active infections are confirmed with full certainty by the positivity of hepatitis B virus or hepatitis C virus nucleic acid tests using polymerase chain reaction technique and also the successful antiviral therapy proved by their negative results. Monitoring of the nucleic acid levels in time can rationalize the type and dosage of antiviral therapy and the length of treatment. Investigations of the nucleotide structure of viral genome, their variants and mutants, the origin of virus infection and the predictive marker of the therapy (interferon, ribavirin, lamivudine) can be determined.
Conclusion: The results of these examinations have greatly contributed to determining the epidemiology of viral hepatitis infections in Hungary, and today they provide indispensable help for the clinician so as to make antiviral therapy protocols optimal.