Despite improvements in serological testing and imaging techniques, the liver biopsy remains an important diagnostic tool for diagnosing diffuse hepatic disease and hepatic lesions. For instance, liver biopsy can confirm specific disorders, leading to specific therapy in a setting of acute liver failure due to acute fatty liver of pregnancy, herpes virus infection, AIH, or Wilson’s disease [8]. The liver biopsy is helpful in identifying the presence of concurrent diseases, something frequently encountered in the setting of viral hepatitis. One study reveals that 20.5 % of viral hepatitis patients had other concurrent processes (e.g., NAFLD, drug-induced liver injury (DILI) , Wilson’s disease , iron overload, PBC) that could potentially modify disease progression and/or alter the management strategy [9]. The liver biopsy not only confirms diagnosis, but may also determine which process is the dominant factor injuring the liver. Liver biopsy can solve the diagnostic dilemma of assessing patients with atypical features, such as anti-mitochondrial antibody-negative PBC or small bile duct PSC. Liver biopsy can distinguish between AIH and steatohepatitis for the obese patient with elevated alanine aminotransferase, IgG, and/or autoimmune markers [2]. Perhaps in no other setting is liver biopsy more essential than in evaluating allograft dysfunction after liver transplantation. It is critical to know the specific diagnosis for management, especially considering the broad potential differential diagnosis comprising acute and chronic cellular rejection, preservation injury, recurrence of the original disease, DILI, ischemic injury, or biliary obstruction. In the patient exposed to supplements or herbal medicines in whom harmful effects are suspected, liver biopsy is instrumental in making and/or confirming the diagnosis of drug-/toxin-related liver injury [10]. Please see question 4 above for the role of liver biopsy in a liver mass lesion, but do keep in mind that these biopsies typically need to be guided by imaging.

Another important role of liver biopsy is to assess the degree of fibrosis to predict liver-related morbidity and mortality. The stage reflects the degree of fibrosis and may not only guide subsequent treatment, but also help to decide whether the patient is at risk for potential complications, including portal hypertensive bleeding and HCC screening, which would be warranted in all patients with advanced fibrosis. Non-invasive methods, such as transient elastography and magnetic resonance elastography, are emerging. For example, FibroScan^® (transient elastography) was approved by the FDA in 2013 for the non-invasive assessment of hepatic fibrosis and is now used in a number of clinics to monitor patients and at times even to justify proceeding with a liver biopsy. Although in the future these tests may replace liver biopsy in staging [11], validation has not been performed in all disease entities and the liver biopsy still remains the gold standard.

A liver biopsy can be used to develop a treatment plan. For example, immunosuppression levels can be adjusted for patients with AIH or liver transplantation based on histological findings. By assessing the efficacy and the toxicity of a new medication, the liver biopsy remains the gold standard.