From the Guidelines
Elevated liver enzymes are a significant indicator of liver damage or dysfunction, and patients with such elevations should consult a healthcare provider immediately to determine the underlying cause and guide appropriate treatment. The significance of elevated liver enzymes, such as alanine transaminase (ALT) and aspartate transaminase (AST), lies in their ability to indicate hepatocellular injury or necrosis, which can be caused by various factors including viral hepatitis, medication toxicity, autoimmune hepatitis, or nonalcoholic fatty liver disease 1.
Normal Ranges and Interpretation
Normal ALT levels are typically in the range of 29 to 33 IU/L (0.48-0.55 mkat/L) in men and 19 to 25 IU/L (0.32-0.42 mkat/L) in women, while normal AST levels can vary but are generally considered to be between 5-40 U/L 1. The interpretation of abnormal liver chemistries must be taken in the clinical context of a given patient, considering factors such as risk factors for liver disease, medications, alcohol consumption, comorbid conditions, and signs and symptoms of hepatic disease 1.
Diagnostic Approach
The evaluation of patients with elevated serum aminotransferases should include a detailed history, inventory of medications, and a physical examination, followed by noninvasive serologic tests to exclude common hepatic diseases 1. If these tests are unremarkable, a decision regarding additional serologic testing versus observation should be based on the clinical scenario. Patients with markedly elevated and/or persistent ALT and AST levels, or those with significant symptoms or evidence of chronic or decompensated liver disease, require a more expeditious and complete initial diagnostic evaluation.
Management and Prevention
Management of elevated liver enzymes typically involves identifying and removing the offending agent, supportive care, and monitoring liver function 1. Patients should avoid alcohol and hepatotoxic medications, including acetaminophen, until cleared by their physician. Further diagnostic workup, including viral hepatitis panels, autoimmune markers, and possibly imaging studies, will likely be necessary to determine the specific etiology and guide appropriate treatment. The severity of abnormal aminotransferase can be classified as mild, moderate, or severe, with moderate and severe elevations indicating significant clinical overlap and potential for serious liver disease 1.
From the FDA Drug Label
Abnormalities in liver enzymes have not been associated with Ursodiol therapy and, in fact, Ursodiol has been shown to decrease liver enzyme levels in liver disease. However, patients given Ursodiol should have SGOT (AST) and SGPT (ALT) measured at the initiation of therapy and thereafter as indicated by the particular clinical circumstances
The significance of elevated liver enzymes is not directly related to ursodiol therapy, as ursodiol has been shown to decrease liver enzyme levels in liver disease. However, it is recommended to monitor liver enzymes (SGOT/AST and SGPT/ALT) in patients given ursodiol, as indicated by clinical circumstances 2.
From the Research
Significance of Elevated Liver Enzymes
Elevated liver enzymes, such as alanine aminotransferase (ALT) and aspartate aminotransferase (AST), are significant indicators of liver damage or disease. The following points highlight the importance of these enzymes:
- Elevated ALT and AST levels are associated with various liver conditions, including acute liver injury, autoimmune hepatitis, and drug-induced liver injury 3, 4, 5, 6.
- The levels of ALT and AST can be used to diagnose and assess the severity of liver diseases, with higher levels indicating more severe damage 3, 7.
- Elevated liver enzymes can also be used to monitor the effectiveness of treatment and predict patient outcomes 5, 6.
- In cases of blunt abdominal trauma, elevated AST and ALT levels can be used to diagnose liver injury and predict its severity, with optimal cut-off values of 106 U/l and 80 U/l, respectively 7.
Causes of Elevated Liver Enzymes
The causes of elevated liver enzymes can be diverse, including:
- Ischemic hepatitis, acute viral hepatitis, and drug-induced liver injury 3.
- Autoimmune hepatitis, primary biliary cirrhosis, and primary sclerosing cholangitis 5, 6.
- Blunt abdominal trauma, which can cause liver injury and elevate AST and ALT levels 7.
Clinical Utility of Liver Enzymes
The measurement of liver enzymes has significant clinical utility, including:
- Diagnosing and assessing liver diseases, such as autoimmune hepatitis and primary biliary cirrhosis 5, 6.
- Monitoring the effectiveness of treatment and predicting patient outcomes 5, 6.
- Identifying patients with liver injury due to blunt abdominal trauma and predicting the severity of the injury 7.
- Developing low-cost point-of-care monitoring systems for ALT and AST levels, which can aid in the early detection and diagnosis of liver diseases 4.