Table 1.

Diagnosis of ALF versus reactivation (flare-up or exacerbation) of chronic hepatitis B

	ALF	HBV reactivation
Clinical context	- No history of chronic liver disease - Recent contact with a new partner	-Family history of chronic HBV disease -History of blood transfusions -Known chronic liver disease. -Known HBsAg -Organ transplantation, bone marrow graft, HIV -Recent immunosuppressive therapy/immunomodulator (anti-TNF alpha, rituximab, etc.) - Discontinuation of anti-HBV treatment
Clinical presentation	Jaundice	Jaundice
Ultrasound	- No ultrasound signs of chronic liver disease	- Hepatomegaly, - Splenomegaly, - Ascites
Biochemistry	- ALT, AST > 1000–2000 IU/L - Bilirubin ↑ - GGT ↑	- ALT, AST > 1000–2000 IU/L - Bilirubin ↑ - GGT ↑ - αFP ↑
Virological markers (serology, HBV viral load)	- Anti-HBc IgM +++ (> 1:1000) - HBsAg + (but may be negative) - HBeAg + - HBV-DNA slightly elevated	- Anti-HBc IgM + (< 1:1000) - HBsAg + (but may be negative) - HBeAg + - HBV-DNA +++ - Combination of low or undetectable anti-HBc IgM Bc plus HBV DNA > log10 IU/mL
HBV viral genotype	- Genotype D - B1/Bj subgenotypes - A1762T/G1764A, G1896A, G1899A and A2339G mutations

ALF acute liver failure