Effective Utilization of Noninvasive Tests for Rule-out and Rule-in Strategy for the Treatment of Nonalcoholic Fatty Liver Disease in a Hepatology Center

To date, many noninvasive tests such as biomarkers, scoring systems, and elastography have been developed. We published the world's first report on the efficacy of Fibroscan in patients with NAFLD (Gut. 2007), and established the global standard cutoff value of MR elastography (CGH 2019). Non-invasive testing methods has high negative predictive value, so they are used for ruled-out screening at primary level. However, it is expected that this strategy will be applied to less than 10% of NAFLD patients. Currently, with the advent of many investigational new drugs, we are now in the next stage of picking up NAFLD patients at risk of progressive NASH (NAS≧4 or F≧2) actively (rule-in) for clinical trials or treatments. The FAST score which uses three parameters (AST, CAP, and LSM) developed, and it has been proposed that it can be used to rule-in patients with high positive predictive value those who require treatment. Furthermore, we have recently proposed the MEFIB index as a new method of rule-in using MRE (Gut 2020). The MEFIB index is a very simple method to identify patients with F2 or higher by selecting patients with combination of FIB-4 ≥ 1.6 and MRE ≥ 3.3 kPa. In the future, it is hoped that an ideal rule in/rule-out strategy will be established for the treatment of NAFLD