Performance of the cobas Hepatitis B virus (HBV) test using the cobas 4800 system and comparison of HBV DNA quantification ability between the COBAS AmpliPrep/COBAS TaqMan HBV test version 2.0 and cobas HBV test.

BACKGROUND: Hepatitis B virus (HBV) DNA levels are used to predict the response to therapy, determine therapy initiation, monitor resistance to therapy, and establish treatment success.

OBJECTIVE: To verify the performance of the cobas HBV test using the cobas 4800 system for HBV DNA quantification and to compare the HBV DNA quantification ability between the cobas HBV test and COBAS AmpliPrep/COBAS TaqMan HBV version 2.0 (CAP/CTM v2.0).

STUDY DESIGN: The precision, linearity, and limit of detection of the cobas HBV test were evaluated using the 4th World Health Organization International Standard material and plasma samples. Clinical samples that yielded quantitative results using the CAP/CTM v2.0 and cobas HBV tests were subjected to correlational analysis.

RESULTS: Three hundred forty-nine samples were subjected to correlational analysis, among which 114 samples showed results above the lower limit of quantification. Comparable results were obtained ([cobas HBV test] = 1.038 × [CAP/CTM v2.0]-0.173, r = 0.914) in 114 samples, which yielded values above the lower limit of quantification. The results for 86.8% of the samples obtained using the cobas HBV test were within 0.5 log10 IU/mL of the CAP/CTM v2.0 results. The total precision values against the low and high positive controls were 1.4% (mean level: 2.25 log10 IU/mL) and 3.2% (mean level: 6.23 log10 IU/mL), respectively. The cobas HBV test demonstrated linearity (1.15-6.75 log10 IU/mL, y = 0.95 × 6 + 0.17, r2  = 0.994).

CONCLUSION: The cobas HBV test showed good correlation with CAP/CTM v2.0, and had good precision and an acceptable limit of detection. The cobas HBV test using the cobas 4800 is a reliable method for quantifying HBV DNA levels in the clinical setting.