title: COBAS AmpliPrep-COBAS TaqMan hepatitis B virus (HBV) test: a novel automated real-time PCR assay for quantification of HBV DNA in plasma.
abstract: Success in antiviral therapy for chronic hepatitis B is supported by highly sensitive PCR-based assays for hepatitis B virus (HBV) DNA. Nucleic acid extraction from biologic specimens is technically demanding, and reliable PCR results depend on it. The performances of the fully automatic system COBAS AmpliPrep-COBAS TaqMan 48 (CAP-CTM; Roche, Branchburg, NJ) for HBV DNA extraction and real-time PCR quantification were assessed and compared to the endpoint PCR COBAS AMPLICOR HBV monitor (CAHBM; Roche). Analytical evaluation with a proficiency panel showed that CAP-CTM quantitated HBV DNA levels in one single run over a wide dynamic range (7 logs) with a close correlation between expected and observed values (r = 0.976, interassay variability below 5%). Clinical evaluation, as tested with samples from 92 HBsAg-positive patients, demonstrated excellent correlation with CAHBM (r = 0.966, mean difference in quantitation = 0.36 log(10) IU/ml). CAP-CTM detected 10% more viremic patients and longer periods of residual viremia in those on therapy. In lamivudine (LAM)-resistant patients, the reduction of HBV DNA after 12 months of Adefovir (ADF) was higher in the combination (LAM+ADF) schedule than in ADF monotherapy (5.1 logs versus 3.5 logs), suggesting a benefit in continuing LAM. CAP-CTM detected HBV DNA in liver biopsy samples from 15% of HBsAg-negative, anti-HBcAg-positive graft donors with no HBV DNA in plasma. The amount of intrahepatic HBV DNA was significantly lower in occult HBV infection than in overt disease. CAP-CTM can improve the management of HBV infection and the assessment of antiviral therapy and drug resistance, supporting further insights in the emerging area of occult HBV infection.
authors.affiliation: Microbiology Laboratory, Molinette Hospital, Turin, Italy.
authors.forename: Tiziano
authors.initials: T
authors.lastname: Allice
authors.forename: Francesco
authors.initials: F
authors.lastname: Cerutti
authors.forename: Fabrizia
authors.initials: F
authors.lastname: Pittaluga
authors.forename: Silvia
authors.initials: S
authors.lastname: Varetto
authors.forename: Silvia
authors.initials: S
authors.lastname: Gabella
authors.forename: Alfredo
authors.initials: A
authors.lastname: Marzano
authors.forename: Alessandro
authors.initials: A
authors.lastname: Franchello
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Colucci
authors.forename: Valeria
authors.initials: V
authors.lastname: Ghisetti
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives / Q000627:therapeutic use; D000998:Antiviral Agents / Q000494:pharmacology / Q000627:therapeutic use; D001331:Automation; D001706:Biopsy; D004279:DNA, Viral / Q000032:analysis / Q000097:blood* / Q000302:isolation & purification; D024882:Drug Resistance, Viral; D006514:Hepatitis B Surface Antigens / Q000097:blood; D006515:Hepatitis B virus / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification*; D019694:Hepatitis B, Chronic / Q000821:virology*; D006801:Humans; D019259:Lamivudine / Q000494:pharmacology / Q000627:therapeutic use; D008099:Liver / Q000821:virology; D021141:Nucleic Acid Amplification Techniques; D063065:Organophosphonates / Q000627:therapeutic use; D016133:Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity; D019914:Taq Polymerase; D014766:Viremia / Q000821:virology*
chemical_list: D000998:Antiviral Agents; D004279:DNA, Viral; D006514:Hepatitis B Surface Antigens; D063065:Organophosphonates; D019259:Lamivudine; C053001:adefovir; D019914:Taq Polymerase; D000225:Adenine