What are the next steps for a patient with elevated AST (Aspartate Aminotransferase) and ALT (Alanine Aminotransferase) levels?

Evaluation and Management of AST 95 and ALT 47

Your patient has an AST:ALT ratio of approximately 2:1, which is highly suggestive of alcoholic liver disease and warrants immediate detailed alcohol history and comprehensive evaluation for chronic liver disease. 1

Initial Assessment Priority

The AST:ALT ratio >2 is the most critical finding here and dramatically narrows your differential diagnosis:

• An AST:ALT ratio >2 is highly suggestive of alcoholic liver disease, with ratios >3 being particularly specific for this diagnosis 1
• In alcoholic hepatitis, 70% of patients demonstrate an AST/ALT ratio >2, and >98% of histologically proven cases show a ratio >1.5 2
• This pattern is distinctly different from nonalcoholic fatty liver disease (NAFLD), which typically presents with an AST:ALT ratio <1 2, 1

Critical alcohol history questions:

• Men: >21 standard drinks/week 1
• Women: >14 standard drinks/week 1
• Duration of consumption (>6 months of >40g/day for women, >50-60g/day for men) 2

Immediate Diagnostic Workup

Complete Liver Panel 2, 1

• Alkaline phosphatase, GGT, total and direct bilirubin, albumin, prothrombin time/INR - these assess for cholestatic patterns and synthetic function
• Normal albumin and bilirubin would indicate preserved liver synthetic function despite hepatocellular injury 2
• Elevated bilirubin with elevated transaminases may indicate possible Hy's Law case requiring urgent attention 1

Viral Hepatitis Serologies 2, 1

• HBsAg, anti-HBc IgM, anti-HCV
• Chronic viral hepatitis commonly presents with fluctuating transaminase elevations 2

Metabolic Assessment 1

• Fasting glucose or HbA1c, fasting lipid panel
• Assess for obesity, diabetes, hypertension as NAFLD risk factors (though less likely given your AST:ALT ratio)

Additional Testing 2

• Creatine kinase (CK) - AST is present in cardiac and skeletal muscle, making this essential to exclude non-hepatic causes 2, 3
• Thyroid function tests - thyroid disorders can cause transaminase elevations 2

Imaging

Order abdominal ultrasound 2, 1:

• Sensitivity 84.8% and specificity 93.6% for detecting moderate-severe hepatic steatosis
• Identifies cirrhosis, masses, biliary obstruction, portal hypertension features
• Can assess for structural abnormalities and focal lesions

Risk Stratification for Cirrhosis

The AST:ALT ratio >2 raises significant concern for advanced fibrosis or cirrhosis:

• Calculate FIB-4 score using age, ALT, AST, and platelet count 2, 1
  • Score >2.67 indicates high risk for advanced fibrosis and warrants hepatology referral
  • Score <1.3 (<2.0 if age >65) indicates low risk with NPV ≥90%
• An AST/ALT ratio ≥1 in the context of chronic liver disease indicates cirrhosis with high specificity 4, 5

Management Based on Etiology

If Alcoholic Liver Disease Confirmed 1

• Immediate alcohol cessation - this is non-negotiable
• Nutritional support
• Monitor for hepatic decompensation (ascites, encephalopathy, coagulopathy)
• Consider corticosteroid therapy if AST >5× ULN with signs of alcoholic hepatitis

If Alternative Diagnosis 2, 1

• Medication review - check all medications against LiverTox® database for hepatotoxic potential
• Discontinue suspected hepatotoxic medications if ALT/AST >3× ULN confirmed on repeat testing
• For NAFLD (less likely): lifestyle modifications with 7-10% weight loss target, 150-300 minutes moderate-intensity exercise weekly

Monitoring Schedule

Repeat liver enzymes in 2-4 weeks to establish trend 2, 1:

• If decreasing: continue monitoring every 4-8 weeks until normalized
• If stable or increasing: repeat within 1-2 weeks and intensify evaluation
• If ALT increases to >5× ULN or bilirubin >2× ULN: urgent hepatology referral required 1

Red Flags Requiring Urgent Action 1

• ALT >5× ULN or rapidly rising levels
• Elevated bilirubin with elevated transaminases
• Signs of hepatic decompensation (coagulopathy, encephalopathy, ascites)
• Evidence of synthetic dysfunction (prolonged PT/INR, low albumin)

Critical Pitfalls to Avoid

• Do not assume NAFLD with an AST:ALT ratio >2 - this pattern is highly specific for alcoholic liver disease and requires thorough alcohol history 1
• Do not overlook non-hepatic causes - check CK to exclude muscle injury, especially if recent exercise or trauma 2, 3
• Do not delay hepatology referral if enzymes remain elevated ≥6 months or if FIB-4 score >2.67 2, 1
• AST can be elevated in cardiac injury, skeletal muscle disorders, kidney disease, and hemolysis - always correlate with clinical context 2, 3, 6