GPT and infection: Prati et al. investigated 6,835 blood donors with ALT levels within the standard range (male: ≤ 40 IU/l, female: ≤ 30 IU/l) who were negative for infections (HBV, HCV, and HIV), had no history of medication, with blood glucose, cholesterol, and triglyceride levels lower than the upper limits of the standard ranges, and had a BMI < 25 kg/m2.