The role of noninvasive tests and liver biopsy in the diagnosis of nonalcoholic fatty liver disease.

Nonalcoholic fatty liver disease (NAFLD) is characterized by hepatic steatosis in the absence of significant alcohol consumption (<40 g/week). The essential metabolic trait is insulin resistance, which is why NAFLD is associated with obesity, diabetes mellitus (DM), hyperlipidemia. Approximately one-quarter of adults with NAFLD present nonalcoholic steatohepatitis (NASH) leading to progressive hepatic fibrosis and finally cirrhosis and hepatocellular carcinoma. If liver biopsy (LB) has traditionally been NAFLD's gold standard, over the past 15 years, its use has undergone an important transformation. In this review, the role of noninvasive tests (serological markers, imaging techniques) in the NAFLD evaluation is analyzed, starting from the low adherence of patients for LB, the complications of the technique, and the increased cost. LB is the only investigation that distinguishes between simple steatosis and NASH. However, in the medical practice, LB has gained lesser value; it is worth mentioning that NASH represents a small proportion compared to NAFLD. For this reason, most patients only show biopsy steatosis, which has a good prognosis. In addition, judging by the appearance of inflammation markers and fibrosis in the diagnosis technique, the use of LB has become increasingly rare in the definition of NASH.