Comparison of the QIAGEN artus HBV QS-RGQ Assay With the Roche COBAS AmpliPrep/COBAS TaqMan HBV Assay for Quantifying Viral DNA in Sera of Chronic Hepatitis B Patients.

BACKGROUND: Hepatitis B virus DNA quantification is essential for managing chronic hepatitis B (CHB). We compared the performance of artus HBV QS-RGQ (QIAGEN GmbH, Germany) and CAP/CTM v2.0 HBV assays (Roche Molecular Diagnostics, USA) in CHB patients. METHODS: A comparative evaluation between two assays was performed with 508 clinical serum samples. Precision, linearity, and the limit of detection (LOD) of QS-RGQ assay was evaluated by using the WHO standard 97/750 and clinical samples. RESULTS: Detection rates and viral loads as determined QS-RGQ assay were significantly lower than those from the CAP/CTM v2.0 assay (52.8% vs 60.6%; 3.55±1.77 IU/mL vs 4.18±1.89 IU/mL, P<0.0001). The kappa coefficient between qualitative results was 0.79 (95% confidence interval, 0.74 to 0.85). Bland-Altman plot found a mean difference of (QS-RGQ - CAP/CTM v2.0)=-0.63 log10 IU/mL (95% limit of agreement, -1.48 to 0.22). Repeatability and total imprecision (% CV) of the QS-RGQ assay were 1.0% and 1.1% at 2,000 IU/mL, and 0.7% and 1.4% at 20,000 IU/mL, respectively. Linearity of this assay ranged from 31.6 to 1.0±107 IU/mL, and the LOD was 2.95 IU/mL. CONCLUSIONS: The artus HBV QS-RGQ assay showed good performance but significantly decreased detection rate and viral load compared with CAP/CTM v2.0 assays. This assay recommends using plasma; however, we used stored serum because of the retrospective study design. Usually HBV DNA quantification is performed in plasma or serum, but sample type and clinical relevance of quantitative values should be considered when determining the clinical application of this reagent.

Performance of Roche CAP/CTM HIV-1 qualitative test version 2.0 using dried blood spots for early infant diagnosis.

In the context of early infant diagnosis (EID) decentralization in sub-Saharan Africa, dried blood spot (DBS) is now widely used for HIV proviral DNA detection in resource-limited settings. A new version of CAP/CTM (version 2) has been introduced, recently by Roche Diagnosis as a new real-time PCR assay to replace previous technologies on qualitative detection of HIV-1 DNA using whole blood and DBS samples. The objective of this study was to evaluate CAP/CTM version 2 compared to CAP/CTM version 1 and Amplicor on DBS. A total of 261 DBS were collected from children aged 4 weeks to 17 months born from HIV-seropositive mothers and tested by the three techniques. CAP/CTM version 2 showed 100% of agreement with Amplicor including 74 positive results and 187 negative results. CAP/CTM version 2 versus CAP/CTM version 1 as well as CAP/CTM version 1 versus Amplicor showed two discordant results giving a sensitivity of 98.6%, specificity of 99.5%, positive predictive value of 98.6% and negative predictive value of 99.5%. The concordance was 99.12% (95% of confidence interval) giving a Kappa coefficient of 0.97 (p<0.001). These findings confirmed the expected good performance of CAP/CTM version 2 for HIV-1 EID.

Comparison of the Roche COBAS AmpliPrep/COBAS TaqMan HIV-1 test v1.0 with v2.0 in HIV-1 viral load quantification.

Roche modified the COBAS AmpliPrep/COBAS TaqMan human immunodeficiency virus type 1 (HIV-1) test version 1.0 (CAP/CTM v1.0), resulting in the COBAS AmpliPrep/COBAS TaqMan HIV-1 test version 2.0 (CAP/CTM v2.0). The aim of this study was to evaluate the performance of the CAP/CTM v2.0 and to compare this performance with that of the CAP/CTM v1.0. The study was conducted in a small local study group in Kaohsiung Medical University Hospital, Kaohsiung, Taiwan. A total of 86 plasma samples from HIV-1-seropositive patients were tested using the two assays. The correlation and concordance of results between the two assays were calculated. The CAP/CTM v2.0 generated higher values than did the CAP/CTM v1.0, and five samples (5.8%) yielded a difference of > 1 log10 copies/mL. In addition, our data show that CAP/CTM v1.0 and CAP/CTM v2.0 yielded relatively consistent values for 23 samples with low viral loads (< 200 copies/mL). Furthermore, when viral loads were in a medium range (2-5 log10 copies/mL), the results of the two assays were more compatible. This study shows a good correlation between CAP/CTM v1.0 and v2.0 in HIV-1 viral load measurement. Further attention must be paid to those cases in which measured viral loads present larger differences between the two assays.

Comparison of the QIAGEN artus HBV QS-RGQ Assay With the Roche COBAS AmpliPrep/COBAS TaqMan HBV Assay for Quantifying Viral DNA in Sera of Chronic Hepatitis B Patients

BACKGROUND: Hepatitis B virus DNA quantification is essential for managing chronic hepatitis B (CHB). We compared the performance of artus HBV QS-RGQ (QIAGEN GmbH, Germany) and CAP/CTM v2.0 HBV assays (Roche Molecular Diagnostics, USA) in CHB patients. METHODS: A comparative evaluation between two assays was performed with 508 clinical serum samples. Precision, linearity, and the limit of detection (LOD) of QS-RGQ assay was evaluated by using the WHO standard 97/750 and clinical samples. RESULTS: Detection rates and viral loads as determined QS-RGQ assay were significantly lower than those from the CAP/CTM v2.0 assay (52.8% vs 60.6%; 3.55±1.77 IU/mL vs 4.18±1.89 IU/mL, P<0.0001). The kappa coefficient between qualitative results was 0.79 (95% confidence interval, 0.74 to 0.85). Bland-Altman plot found a mean difference of (QS-RGQ − CAP/CTM v2.0)=−0.63 log₁₀ IU/mL (95% limit of agreement, −1.48 to 0.22). Repeatability and total imprecision (% CV) of the QS-RGQ assay were 1.0% and 1.1% at 2,000 IU/mL, and 0.7% and 1.4% at 20,000 IU/mL, respectively. Linearity of this assay ranged from 31.6 to 1.0±10⁷ IU/mL, and the LOD was 2.95 IU/mL. CONCLUSIONS: The artus HBV QS-RGQ assay showed good performance but significantly decreased detection rate and viral load compared with CAP/CTM v2.0 assays. This assay recommends using plasma; however, we used stored serum because of the retrospective study design. Usually HBV DNA quantification is performed in plasma or serum, but sample type and clinical relevance of quantitative values should be considered when determining the clinical application of this reagent.