The Cobas Taqman assay for hepatitis B virus (HBV) DNA showed linear detection over 7 logs for genotypes A to D. The coefficient of variation was 1.2% at > or =1,000 IU/ml and 22.0% at 10 IU/ml. In 97 clinical samples, the log HBV DNA/ml differed by 0.11 between Cobas Amplicor and Cobas Taqman (r2 = 0.97).

The measurement of hepatitis B virus (HBV) DNA is important for the assessment of liver disease and treatment efficacy. Most commercially available assays for the determination of HBV DNA levels have limited linear ranges. This study was performed to evaluate the clinical performance of the Digene Hybrid Capture II (Digene HC II assay) and the COBAS AMPLICOR Monitor test (COBAS-AM assay), with ...

Elevated HIV-1 viral load (VL) observed in specimens frozen in situ in plasma preparation tubes (PPTs) compared to EDTA plasma specimens may affect therapeutic monitoring of HIV-infected patients. The increase in viral load is cell associated and minimized when plasma from the PPT is aspirated or recentrifuged prior to freezing. This study investigates the contribution of integrated HIV-1 provi...

Sensitive and accurate quantification of hepatitis B virus (HBV) DNA is necessary for monitoring patients with chronic hepatitis receiving antiviral therapy in order to determine treatment response and to adapt therapy in case of inadequate virologic control. The development of quantitative PCR assays has been crucial in meeting these needs. The objective of this study was to compare the perfor...

Plasma specimens collected in 1999 from 32 human immunodeficiency virus type 1 (HIV-1)-infected foreigners living in Madrid, Spain, were examined for the presence of non-B subtypes. Furthermore, plasma viremia was quantified using two different AMPLICOR HIV-1 MONITOR tests, version 1.0 and the new upgraded and automated version 1.5 (COBAS). Most patients came from Africa, where they most likely...

Performances of the new 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 with the endpoint PCR COBAS AMPLICOR HBV Monitor (CAHBM, Roche). Analytical evaluation with proficiency panels from UK National External Quality Assessment Scheme (UK NEQAS) over a 1-year period of distribut...

Plasma specimens collected in 1999 from 32 human immunodeficiency virus type 1 (HIV-1)-infected foreigners living in Madrid, Spain, were examined for the presence of non-B subtypes. Furthermore, plasma viremia was quantified using two different AMPLICOR HIV-1 MONITOR tests, version 1.0 and the new upgraded and automated version 1.5 (COBAS). Most patients came from Africa, where they most likely...

BACKGROUND Low levels of Cytomegalovirus (CMV) viral load are frequently detected following allogeneic stem cell transplantation (SCT) and CMV disease may still develop in some allogeneic SCT patients who have negative pp65-antigenemia (pp65-Ag) or undetectable DNA. Pp65Ag is a sensitive method to diagnose CMV infection. Quantitative CMV-DNA PCR assay in plasma has been proposed to monitor CMV ...