Performance Comparison of the HBV QS-RGQ and the CAP/CTM HBV v2.0 Assays regarding Hepatitis B Virus DNA Quantification.

Background: Over 240 million people are chronically infected with hepatitis B virus (HBV), the leading cause of liver cancer worldwide. The quantification of the HBV DNA level is critical for monitoring the efficacy of antiviral treatment of chronic HBV patients.

Methods: In our study, we compared the performance of the HBV QS-RGQ assay to the CAP/CTM v2.0 test, as a reference method, on 142 Moroccan patients. The analytical performance of the HBV QS-RGQ assay, such as the limit of detection, quantification, precision, reproducibility, and linearity, was determined using dilution series from 10 to 0.1 log IU/mL.

Results: Detection rates and viral loads quantified by the HBV QS-RGQ assay were significantly lower than those from the CAP/CTM v2.0 assay (73.94% vs. 82.39%; 3.34 ± 1.94 log IU/mL vs. 3.91 ± 2.45 log IU/mL; < 0.01). A Bland-Altman plot found a mean difference of (CAP/CTM v2.0 -  HBV QS - RGQ) = 0.5717 log IU/mL, with an average range of -1.13 to 2.31 log IU/mL. The two methods demonstrated a high correlation ( = 0.88) for 100 positive samples, a moderate correlation for samples below 2000 IU/mL ( = 0.76), and a very high correlation for the samples above 2000 IU/mL ( = 0.95). Linearity of the QS-RGQ test ranged from 1.07 to 7.51 log IU/mL.

Conclusion: The HBV QS-RGQ assay showed a strong correlation, precision, and linearity in comparison with the CAP/CTM v2.0. However, viral loads determined by the HBV QS-RGQ assay were lower than those determined by the CAP/CTM v2.0 assay.