Abstract
The detection of abnormal liver biochemical test levels is often the first indication of the presence of liver disease. The pattern of abnormalities can provide clues to the etiology of hepatic dysfunction; for example, elevated serum aminotransferase levels are typical of viral hepatitis, whereas a predominant elevation of the alkaline phosphatase level is more typical of cholestatic disorders such as primary biliary cholangitis and primary sclerosing cholangitis. Precise diagnosis of hepatic dysfunction requires additional workup, including serologic tests and imaging studies. For some causes of liver disease, such as drug-induced liver disease and nonalcoholic fatty liver disease, specific testing is not available, and diagnosis is by exclusion of other etiologies. Liver biopsy is increasingly reserved for hepatic dysfunction of unknown cause. The severity of liver disease is best assessed with tests of hepatic function, specifically the serum total bilirubin level, albumin level, and international normalized ratio.