GPT and viral infectious disease: The normal concentration of ALT in blood serum ranges from 5–35 U/L (0.1–0.7 μg/mL), [29] and serum ALT levels increase up to 50-fold in connection with a variety of liver conditions, including viral infection, cirrhosis, non-alcoholic steatohepatitis, and drug toxicity [31], [33], [34].