Table 1.

Phases of HBV reactivation [24,26].

Virological Changes
HBsAg negative to HBsAg positive	There is little clinical significance as it would not affect the care of myeloma treatment.
HBV DNA rising by 10-fold	Viral replication increases gradually. However, serum ALT and AST levels are normal and patients are asymptomatic. Increase in HBV DNA by 10-fold has little effect on chemotherapy.
Clinically significances
HBV reactivation with hepatitis	ALT or AST levels become abnormal but not so high (2–10 times the upper limit of normal or baseline levels). This is important clinically as it might affect myeloma care.
Severe hepatitis without liver failure	ALT or AST levels become >10 times the upper limit of normal or baseline levels. PT-INR remains normal. This is important as it might lead to liver failure despite treatment with HBV antiviral therapy.
Fulminant hepatitis/death
Severe hepatitis leading to liver failure	Liver failure is defined as (1) elevation in serum bilirubin level (>2 mg/dL) and prolongation of prothrombin time (PT-INR >1.3), (2) ascites or (3) encephalopathy. This is important as it can lead to death despite antiviral therapy.

Abbreviations: ALT, alanine aminotransferase; AST, aspartate aminotransferase; PT-INR, prothrombin time international normalized ratio.