In carriers with inactive infection or with evidence of resolved hepatitis B, reactivation can occur and manifest itself by: (a) an active process of necroinflammation with a ≥5-fold increase in serum ALT activity above the normal upper limit, (b) absolute increase on ALT levels ≥100 IU/mL associated to ≥1 log10 elevation of viral load compared to the pre-exacerbation period, or (c) absolute HBV-DNA increase exceeding 108 copies/mL regardless of ALT activity levels [80]. Here, GPT is linked to hepatitis B virus infection.