Inclusion Criteria:  Subject aged ≥ 18 years, Subject who has provided consent (oral or written) or sample collected under waiver With sufficient volume to perform clinical trial testing  And belonging to one of the following enrollment groups:  Unselected blood donors Hospitalized patients Presumed HBsAg positive patients by Confirmatory testing of a CE-marked assay Patients having recovered from natural HBV infection, presumed Anti-HBs positive (i.e. Anti-HBs and Anti-HBc Total positive by CE-marked assays) Patients having received HBV vaccination, presumed Anti-HBs positive (confirmed by testing at the time of enrollment, i.e. positive for Anti-HBs and negative for Anti-HBc by CE-marked assays). Presumed Anti-HBc Total positive patients by a CE-marked assay Presumed Anti-HBc IgM positive patients by a CE-marked assay with acute/recent HBV infection 8 Presumed HBeAg positive patients by a CE-marked assay Presumed Anti-HBe positive patients by a CE-marked assay Patients with chronic HBV infection  Exclusion Criteria:  Samples from subjects already included in the study* (* Patient can be included only once per HBV marker study, but can potentially be enrolled for several separate HBV marker studies.)