The Use of Liver Biopsy in Nonalcoholic Fatty Liver Disease: When to Biopsy and in Whom

Key points

Natural history and clinical features of nonalcoholic fatty liver disease

NAFLD can be divided into 2 categories: benign steatosis, also referred to as isolated fatty liver or NAFL, and NASH. NAFL is present in about 66% to 80% of patients with NAFLD.1, 2, 4 Long-term studies have demonstrated that patients with NAFL have less than a 1% chance of developing fibrosis progression to cirrhosis or liver-related mortality over 15 years.17, 18, 19, 20, 21 Long-term survival is similar to that of the general population. In contrast, 20% to 33% of patients with NAFLD have

Recognition of patients with nonalcoholic fatty liver disease

An elevation in serum liver transaminases, either aspartate transaminase (AST) and/or alanine transaminase (ALT), is often the first hint that patients may have NAFLD. Serologic studies should be performed in such patients to exclude all other causes of chronic liver disease. NAFLD is suspected when all serologic studies are negative. However, many patients with NAFLD may have a moderate elevation in serum ferritin, some have a positive antinuclear (ANA) smooth muscle antibody (ASMA), and

Noninvasive markers of nonalcoholic fatty liver disease

Once patients are suspected of having NAFLD, several noninvasive tests can be used to help confirm this is correct and to determine if this is NAFL or NASH. Cytokeratin (CK)-18 is a serum marker that is increased in patients with hepatocyte apoptosis and is thought to be relatively specific for NASH as opposed to being a general marker of apoptosis from other forms of chronic liver disease. Elevations in CK-18 greater than 210 u/L are suggestive of NASH.32, 37 Unfortunately, CK-18 is not a

What is learned by performing liver biopsy in patients with suspected nonalcoholic fatty liver disease

The goals of performing a liver biopsy in patients suspected of having NAFLD are to confirm this diagnosis, exclude other causes of chronic liver disease, determine if patients have NAFL or NASH, and to demonstrate if patients have cirrhosis. A diagnosis of NAFLD requires that there is at last 5% steatosis in the liver biopsy specimen.1, 2, 3 The NAFLD Activity Score (NAS) is a useful system to assess liver injury in patients with NAFLD and response to therapy for patients enrolled in clinical

In whom and when should a liver biopsy be performed

It is not necessary to perform a liver biopsy in all patients suspected of having NAFLD.15, 16 A liver biopsy should only be performed if it will alter your treatment recommendations for patients, make patients aware they have a serious liver condition, or to confirm or exclude NAFLD in patients with conflicting clinical data. The data that you should use to decide on whether to perform a liver biopsy include liver transaminases, liver ultrasound, serologic studies for other causes of liver

Summary

NAFLD is common in the United States and throughout the world and leads to cirrhosis in a significant percentage of patients. Most patients with NAFLD are identified because they are found to have a liver ultrasound or other imaging study suggesting fatty liver with or without an elevation in liver transaminases. A presumptive diagnosis of NAFLD is correct once other causes of chronic liver disease have been excluded with appropriate serologic testing. NAFLD can exist as NAFL, which does not