A European multicientre study on the comparison of HBV viral loads between VERIS HBV assay and Roche COBAS® TAQMAN® HBV test, Abbott RealTime HBV assay, Siemens VERSANT HBV assay, and Qiagen artus HBV RG kit.

BACKGROUND: Hepatitis B viral load testing is essential to treatment and monitoring decisions in patients with chronic Hepatitis B. Beckman Coulter has developed the VERIS HBV Assay (Veris) for use on the fully automated DxN VERIS Molecular Diagnostics System.1 OBJECTIVES: To evaluate the clinical performance of the Veris HBV Assay at multiple EU laboratories STUDY DESIGN: Method comparison was performed with a total of 344 plasma specimens from HBV infected patients tested with Veris and COBAS® TaqMan® HBV Test (Cobas), 207 specimens tested with Veris and RealTime HBV Assay (RealTime), 86 specimens tested with Veris and VERSANT® HBV Assay (Versant), and 74 specimens tested with Veris and artus® HBV RG PCR kit (artus). RESULTS: Bland-Altman analysis showed average bias of -0.46 log10 IU/mL between Veris and Cobas, -0.46 log10IU/mL between Veris and RealTime, -0.36 log10IU/mL between Veris and Versant, and -0.12 log10IU/mL between Veris and artus. Bias was consistent across the assay range. Patient monitoring results using Veris demonstrated similar viral load trends over time to Cobas, RealTime, and artus. CONCLUSIONS: The VERIS HBV Assay demonstrated comparable clinical performance, with varying degrees of negative bias, compared to other currently marketed assays for HBV DNA monitoring. This negative bias should be taken into consideration if switching monitoring methods to Veris.

Real-time PCR assays for hepatitis B virus DNA quantification may require two different targets.

BACKGROUND: Quantification Hepatitis B virus (HBV) DNA plays a critical role in the management of chronic HBV infections. However, HBV is a DNA virus with high levels of genetic variation, and drug-resistant mutations have emerged with the use of antiviral drugs. If a mutation caused a sequence mismatched in the primer or probe of a commercial DNA quantification kit, this would lead to an underestimation of the viral load of the sample. The aim of this study was to determine whether commercial kits, which use only one pair of primers and a single probe, accurately quantify the HBV DNA levels and to develop an improved duplex real-time PCR assay. METHODS: We developed a new duplex real-time PCR assay that used two pairs of primers and two probes based on the conserved S and C regions of the HBV genome. We performed HBV DNA quantitative detection of HBV samples and compared the results of our duplex real-time PCR assays with the COBAS TaqMan HBV Test version 2 and Daan real-time PCR assays. The target region of the discordant sample was amplified, sequenced, and validated using plasmid. RESULTS: The results of the duplex real-time PCR were in good accordance with the commercial COBAS TaqMan HBV Test version 2 and Daan real-time PCR assays. We showed that two samples from Chinese HBV infections underestimated viral loads when quantified by the Roche kit because of a mismatch between the viral sequence and the reverse primer of the Roche kit. The HBV DNA levels of six samples were undervalued by duplex real-time PCR assays of the C region because of mutations in the primer of C region. CONCLUSIONS: We developed a new duplex real-time PCR assay, and the results of this assay were similar to the results of commercial kits. The HBV DNA level could be undervalued when using the COBAS TaqMan HBV Test version 2 for Chinese HBV infections owing to a mismatch with the primer/probe. A duplex real-time PCR assay based on the S and C regions could solve this problem to some extent.

Quantification of intrahepatic total HBV DNA in liver biopsies of HBV-infected patients by a modified version of COBAS® Ampliprep/COBAS®TaqMan HBV test v2.0.

Intrahepatic total HBV DNA (it-HBV DNA) level might reflect the size of virus reservoir and correlate with the histological status of the liver. To quantitate it-HBV DNA in a series of 70 liver biopsies obtained from hepatitis B chronic patients, a modified version of the COBAS®Ampliprep/COBAS®TaqMan HBV test v2.0 was used for this purpose. The linearity and reproducibility of the modified protocol was tested by quantifying serial dilutions of a full-length HBV containing plasmid and it-HBV DNA from a reference patient. A good linear trend between the expected values and those generated by the assay was observed at different concentrations of both plasmid and reference patient (R 2 = 0.994 and 0.962, respectively). Differences between the values obtained in two independent runs were ≤0.3 log IU for the plasmid and ≤0.6 log IU/mg for the reference patient, showing a high inter-run reproducibility. In the 70 liver biopsies, it-HBV DNA level ranged from 1.4 to 5.4 log IU/mg, with a good linearity and reproducibility between the values obtained in two runs [R 2 = 0.981; median (IQR) difference of it-HBV DNA 0.05 (0.02-0.09) IU/mg]. The modified COBAS®Ampliprep/COBAS®TaqMan HBV test v2.0 allows an accurate quantitation of it-HBV DNA. Its determination may have prognostic value and may be a useful tool for the new therapeutic strategies aimed at eradicating the HBV infection.

An in-house real-time polymerase chain reaction: standardisation and comparison with the Cobas Amplicor HBV monitor and Cobas AmpliPrep/Cobas TaqMan HBV tests for the quantification of hepatitis B virus DNA

This study aimed to standardise an in-house real-time polymerase chain reaction (rtPCR) to allow quantification of hepatitis B virus (HBV) DNA in serum or plasma samples, and to compare this method with two commercial assays, the Cobas Amplicor HBV monitor and the Cobas AmpliPrep/Cobas TaqMan HBV test. Samples from 397 patients from the state of São Paulo were analysed by all three methods. Fifty-two samples were from patients who were human immunodeficiency virus and hepatitis C virus positive, but HBV negative. Genotypes were characterised, and the viral load was measure in each sample. The in-house rtPCR showed an excellent success rate compared with commercial tests; inter-assay and intra-assay coefficients correlated with commercial tests (r = 0.96 and r = 0.913, p < 0.001) and the in-house test showed no genotype-dependent differences in detection and quantification rates. The in-house assay tested in this study could be used for screening and quantifying HBV DNA in order to monitor patients during therapy.

Comparison of the Abbott RealTime HBV assay with the Roche Cobas AmpliPrep/Cobas TaqMan HBV assay for HBV DNA detection and quantification.

BACKGROUND: Measurement of hepatitis B virus (HBV) DNA levels is essential in the clinical management of patients with chronic HBV infection. Performance and accuracy of quantitation for HBV DNA are therefore critical in clinical practice. OBJECTIVES: We aimed to compare and evaluate the performance characteristics of two HBV DNA quantitative assays: Abbott RealTime HBV (RealTime assay) and Cobas AmpliPrep/Cobas TaqMan HBV assays 2.0 (TaqMan assay). STUDY DESIGN: Serum samples from 220 HBV-infected patients were collected. Performance characteristics of the HBV DNA quantitative assays, including sensitivity, linearity, and reproducibility were measured. The assays were compared based on the viral status, including HBeAg, genotype, core promoter and pre-core region mutations. RESULTS: The RealTime assay had a sensitivity and specificity of 98.2% and 100%, respectively. The intra-assay coefficients of variation of serum samples ranged from 0.00% to 11.25% for the RealTime assay and 1.22% to 8.22% for TaqMan assay. Paired quantitative results showed excellent correlation by linear regression analysis (R(2)=0.961), good level of agreement with a mean difference of 0.31log10IU/mL, and limits of agreement of -0.62 to 1.24log10IU/mL, irrespective of HBeAg, genotype, core promoter and pre-core region mutation-specific differences. In this study, a difference of ≥1log10IU/mL between the two assays was observed in 8.6% of the samples. Genotype B and average HBV DNA levels of <3log10IU/mL were significant associated factors of this discordance. CONCLUSIONS: The Abbott assay delivered high performance for HBV DNA quantification and correlated extremely well with the TaqMan assay, irrespective of viral status.

Comparison of detection and quantification of HBV DNA in chronic HBeAg negative and positive patients by Abbott RealTime HBV and Roche Cobas TaqMan HBV assays.

Monitoring the serum hepatitis B viral DNA levels with sensitive realtime PCR assays is strongly recommended for the management of patients with chronic HBV infection. This study compares the performance of two realtime HBV quantitative PCR assays with samples from chronic HBeAg(+) and HBeAg(-) patients.