Evaluation of the Xpert HBV Viral Load for hepatitis B virus molecular testing

Background: Accurate molecular methods to detect and quantify hepatitis B virus (HBV) DNA are essential to diagnose chronic infections, guide treatment decisions, assess response to treatment, and determine risk of HBV-related complications. New HBV DNA generations of real-time assay platforms are now available with the availability of results in less than 2-3 h and a continuous loading of specimens with true random access. Objectives: The aim of this prospective study was to evaluate the performance of the new Xpert HBV Viral Load assay to accurately quantify HBV DNA in plasma and in whole blood collected on dried blood spot (DBS). Methods: Plasma and whole blood from 143 patients chronically infected with HBV were tested in parallel using two commercially real-time PCR assay (Cobas AmpliPrep/Cobas Taqman HBV test, version 2.0, and Xpert HBV Viral Load assay). Results: HBV DNA levels in whole blood strongly correlated with those measured in plasma. A positive significant correlation between the HBV DNA levels in plasma measured with the new Xpert HBV Viral Load and CAP/CTM HBV v2.0 assays was found. Conclusions: The newly developed real-time PCR-based assay Xpert HBV Viral Load accurately quantifies HBV DNA in whole blood specimens as well as in plasma samples from patients with chronic HBV infection. Whole blood specimens collected on DBS can be confidently used for replicative HBV infection detection in patients with HBV DNA level above 3 Log using standardized, commercially available methods.