Table 2.

Definitions of HBV reactivation based on different society guidelines.

Society	Reactivaion of CHB	Reactivation of Resolved HBV
American Association for the Study of Liver Diseases (AASLD) 2018 guideline [2]	Any of the following: Unavailable DNA baseline: ≥10,000 IU/mL Available DNA baseline, previously undetectable: ≥1000 IU/mL Available DNA baseline, previously detectable: ≥100-fold increase	Any of the following: Development of detectable DNA Reappearance of HBsAg (also known as reverse seroconversion)
American Gastroenterological Association (AGA) 2015 guideline [6]	Unavailable DNA baseline: not explicitly defined Available DNA baseline, previously undetectable: de novo detectable DNA Available DNA baseline, previously detectable: ≥10-fold increase	Reverse seroconversion to HBsAg-positive status
The Asian Pacific Association for the Study of the Liver (APASL) 2016 guideline [7]	Unavailable DNA baseline: ≥20,000 IU/mL Available DNA baseline, previously undetectable: de novo detectable HBV DNA to a level of 100 IU/mL Available DNA baseline, previously detectable: ≥2 log increase from baseline levels	Not clearly defined
European Association for the Study of the Liver (EASL) 2017 guideline [3]	No clearly defined	Not clearly defined
Korean Association for the Study of the Liver (KASL) 2019 guideline [8]	An increase in serum HBV DNA by more than 100 times the baseline level	Seroconversion of HBsAg-negative to positive Detection of serum HBV DNA from none to positive
American Society of Clinical Oncology (ASCO) 2020 update [9]	The same as the AASLD guidelines	The same as the AASLD guidelines