From the Guidelines
Elevation of AST and ALT levels in a patient for the first time indicates hepatocellular injury, which can be caused by various factors including fatty liver disease, viral hepatitis, autoimmune hepatitis, and medications/toxins, and warrants further investigation and lifestyle modifications.
Initial Steps
When a patient presents with first-time elevated AST and ALT levels, the following steps should be taken:
- Repeat the liver function tests in 2-4 weeks to confirm the results 1
- Avoid alcohol consumption and review all medications, including over-the-counter drugs and supplements, with the healthcare provider 1
Further Investigation
If the levels remain elevated, further investigation is warranted, including:
- Comprehensive metabolic panel to assess for underlying metabolic disorders 1
- Complete blood count to rule out hemolysis or other hematological disorders 1
- Possibly an ultrasound of the liver to assess for fatty liver disease or other liver pathology 1
Lifestyle Modifications
Lifestyle modifications such as weight loss (if overweight) and increasing physical activity may be beneficial in reducing liver enzyme levels and improving overall liver health 1
Referral to Specialist
If AST or ALT levels are more than three times the upper limit of normal, or if they remain persistently elevated after initial interventions, referral to a hepatologist or gastroenterologist is recommended to further evaluate and manage the underlying cause of the liver enzyme elevation 1
Common Causes
Common causes of mild increases in aminotransferases include nonalcoholic fatty liver disease (NAFLD) and alcohol-induced liver disease, while uncommon causes include drug-induced liver injury, hepatitis B, hepatitis C, and hereditary hemochromatosis 1
Severity Classification
The severity of abnormal aminotransferase can be classified as mild, moderate, or severe, with moderate and severe elevations indicating significant liver damage and warranting prompt medical attention 1
From the Research
Elevation of AST and ALT
Elevation of Aspartate Aminotransferase (AST) and Alanine Aminotransferase (ALT) in a patient for the first time can indicate various conditions. The causes of elevated AST and ALT can be categorized into hepatic and non-hepatic causes.
Hepatic Causes
- Chronic alcohol consumption 2
- Non-alcoholic steatohepatitis (NASH) 2, 3
- Chronic viral hepatitis 2, 3
- Metabolic dysfunction-associated steatotic liver disease (MASLD) 3
- Alcoholic liver disease 3
- Drug-induced liver injury 3
- Hereditary hemochromatosis 3
- Alpha1-antitrypsin deficiency 3
- Autoimmune hepatitis 3
- Wilson disease 3
Non-Hepatic Causes
- Polymyositis 2
- Acute muscle injury 2
- Acute myocardial infarction 2, 4
- Hypothyroidism 2
- Celiac disease 3
- Hyperthyroidism 3
- Rhabdomyolysis 3
- Pregnancy-associated liver disease 3
Clinical Implications
Elevation of AST and ALT can be associated with significant underlying liver disease and increased risk of liver-related and all-cause mortality 3. However, intraindividual variability in liver function test results is high, and more than 30% of adults with elevated AST, ALT, or bilirubin levels would be reclassified as normal if retested 5. Elevated AST and AST/ALT levels have also been correlated with severity of COVID-19 and mortality 6.