GPT and fatty liver disease: Accordingly, serum ALT levels were higher in the patients with grade II (40.48 ± 28.64 IU/L) and grade III (42.52 ± 20.57 IU/L) liver steatosis compared to those with grade I liver steatosis (23.23 ± 11.25 IU/L) and the group without NAFLD (25.40 ± 15 IU/L).