Fully automated quantitation of hepatitis B virus (HBV) DNA in human plasma by the COBAS AmpliPrep/COBAS TaqMan system.

BACKGROUND: The measurement of HBV DNA levels has become the most direct and reliable method used for accurate diagnosis and prognosis of acute and chronic HBV infection ]. Nucleic acid amplification testing (NAT detection) also reduces the pre-seroconversion window period. The method can be used to aid in the management of HBV infection, by the identification of individuals with high levels of viral replication who might benefit from antiviral therapy, monitoring patients on therapy, and identification of the development of resistance. OBJECTIVES: Evaluation of the novel COBAS AmpliPrep/COBAS TaqMan HBV Test, which combines automated extraction of DNA on the COBAS AmpliPrep Instrument (CAP), coupled with real-time PCR on the COBAS TaqMan Analyzer (CTM), thus greatly reducing hands-on time during sample preparation and amplification/detection. The assay fulfils the current requirements: a highly sensitive HBV DNA detection reagent which is calibrated to the International WHO Standard to reliably quantify HBV genotypes A-G in plasma with a very broad measuring range, thereby minimizing laborious repeat testing. STUDY DESIGN: The test was evaluated for sensitivity, dynamic range, precision, clinical and analytical specificity, genotype inclusivity, interfering substances, and correlation with other tests for the detection of HBV DNA (COBAS Amplicor HBV Monitor Test, COBAS TaqMan HBV Test for Use with the High Pure System and VERSANT HBV DNA 3.0 Assay). RESULTS AND CONCLUSION: A fully automated system for sample preparation, amplification and quantitation of HBV DNA was developed that demonstrates a nearly 7-log dynamic range up to 1.1E+08IU/mL, an assay sensitivity (95% hit-rate) of 4-12IU/mL and an equivalent detection of genotypes A-G plus a prevalent pre-core mutant. The results obtained with the new test show a good correlation to titers obtained with other platforms.