Asymptomatic patients with abnormal results on liver function test pose a diagnostic challenge. In general, determinations of routinely ordered tests of liver function are neither sensitive nor specific for liver disease. Fatty liver, alcohol-related liver damage and chronic viral hepatitis are the most common causes of abnormal liver function test results in asymptomatic patients. Causes of asymptomatic liver disease include hemochromatosis, Wilson's disease, drug toxicity, chronic autoimmune hepatitis, biliary cirrhosis, sclerosing cholangitis, alpha1-antitrypsin deficiency and sarcoidosis. The most efficient screening tests for liver damage are alanine transaminase, alkaline phosphatase and bilirubin. Repeat testing when results are abnormal, and use of ancillary tests, such as creatine phosphokinase or gamma-glutamyl-transferase, may confirm liver damage. Imaging studies help exclude biliary obstruction or neoplasm. Treatable illnesses should be ruled out. Three to six months of observation for progressive symptoms and liver dysfunction may follow. After the period of observation, further laboratory tests, a diagnostic liver biopsy and/or referral to gastroenterologist may be needed.