Flowchart illustrating the strategy for preventing hepatitis due to HBV reactivation. All patients are screened before starting anti-B-cell therapy by measuring serum HBV markers including HBsAg, anti-HBc, and anti-HBs to identify groups at risk of HBV reactivation. If an individual is seronegative for HBsAg but seropositive for anti-HBc and/or anti-HBs, baseline HBV DNA levels are measured in addition to the serum markers. To prevent hepatitis due to HBV reactivation after anti-B-cell therapy, antiviral prophylaxis is recommended for HBsAg-positive patients and/or patients in whom HBV DNA is detectable at baseline, whereas regular monitoring of HBV DNA-guided preemptive antiviral therapy is a reasonable approach for patients with resolved HBV infection who are seronegative for HBsAg but seropositive for anti-HBc and/or anti-HBs. This figure is modified and cited from Kusumoto et al⁷  with permission from The Japanese Society of Hematology.