The Korean Journal of Hepatology∙pISSN: 1738-222X eISSN: 2093-8047

Nonalcoholic fatty liver disease (NAFLD) is no longer considered to be a normal physiologic condition without any clinical significance. It is now widely accepted that nonalcoholic steatohepatitis (NASH), a type of fatty liver disease, can progress to end-stage liver disease and increase the risk of mortality. In addition, NAFLD patients are associated with a significantly higher overall mortality as well as liver-related mortality compared to the age- and gender-adjusted general population.1,2 Accordingly, several studies have been conducted to redefine the normal ranges of liver function tests, especially alanine aminotransferase (ALT) levels considering the influence of NAFLD on serum ALT level. However, there are two different ways to interpret ALT levels. Piton et al suggested that these levels should be interpreted with respect to the body mass index (BMI