GPT and infection: These data suggest that liver function is noticeably impacted during most infections, even if peak ALT levels in plasma donors were typically lower than those reported for cases of acute viral hepatitis in general (300–3,000 IU/L) (19) and acute hepatitis A in particular (mean 2,000 IU/L and levels >5,000 IU/L for 10% of cases) (20).