GPT and steatosis: Abnormal enzyme liver function tests (serum aminotransferase enzymes) and non-invasive methods (ultrasound or 1H-magnetic-resonance spectroscopy) are used to diagnose liver disease such as steatosis.11 Steatosis is usually diagnosed by the measurement of gamma-glutamyl transferase (GGT) and alanine aminotransferase (ALT)12 and in addition ultrasonography.