Noninvasive Diagnosis of NASH and Liver Fibrosis Within the Spectrum of NAFLD.

Nonalcoholic fatty liver disease (NAFLD) is the most common type of chronic liver disease in the United States, affecting an estimated 70 million Americans. The histologic spectrum of NAFLD ranges from simple steatosis to nonalcoholic steatohepatitis (NASH), fibrosis, and eventually cirrhosis. Patients with NASH and significant fibrosis seen on liver biopsy have an increased risk for liver-related morbidity and mortality compared to patients with simple steatosis. Due to the high prevalence of NAFLD, there has been an urgent need to develop reliable noninvasive markers and tests that can accurately predict the presence of advanced disease without the need for liver biopsy. These tests can be divided into 2 groups: those that predict the presence of NASH (such as markers of hepatocyte apoptosis, oxidative stress, and inflammation, as well as predictive models based on clinical variables) and those that predict the presence of fibrosis (such as simple and complex predictive models). This paper provides an overview of various noninvasive methods for detecting NAFLD and suggests a diagnostic algorithm that can be used in clinical practice.