BRD2 and hepatitis B virus infection: Additionally, six cases of occult hepatitis B infection (OBI) were identified, with one case (0.03%) being solely detected through positive molecular screening (HBV NAT) and the remaining five cases (0.2%) being identified through both HBV NAT and positive anti-HBc, which would have been undetectable prior to the implementation of molecular screening (NAT HBV).