What is the appropriate workup for non‑alcoholic steatohepatitis (NASH)?

NASH Workup

Begin with FIB-4 score or NAFLD fibrosis score as your first-line noninvasive test to risk-stratify for advanced fibrosis, followed by confirmatory testing with transient elastography or Enhanced Liver Fibrosis (ELF) test for indeterminate results, and reserve liver biopsy for diagnostic uncertainty or when considering patients for NASH-specific drug therapies 1, 2.

Initial Assessment and Risk Stratification

Who to Screen

• Actively look for NAFLD/NASH in patients with Type 2 diabetes or metabolic syndrome 1. Do not wait for abnormal liver enzymes—they are unreliable for detecting liver disease 1.
• If ultrasound incidentally shows steatosis or liver enzymes are persistently abnormal without explanation, immediately proceed to fibrosis risk assessment 1.

First-Line Noninvasive Testing

Calculate FIB-4 score (age, ALT, AST, platelet count) as your primary tool 2:

• FIB-4 <1.3: Low risk of advanced fibrosis—manage in primary care with lifestyle modification and cardiovascular risk reduction. Reassess in 3 years 1, 2.
• FIB-4 1.3-2.67 (or 1.24-1.45 range): Indeterminate risk—requires secondary testing with transient elastography (VCTE) or ELF test 1, 2.
• FIB-4 >2.67: High risk—refer to hepatology 1.

Why FIB-4? It has a 92.7% negative predictive value for excluding advanced fibrosis, is free, and is the most validated simple score 2. NAFLD fibrosis score is an acceptable alternative with similar performance (91.8% NPV) 2.

Secondary Care Evaluation

Confirmatory Testing for Indeterminate Risk

When FIB-4 is indeterminate, use imaging-based elastography 1, 2:

Vibration Controlled Transient Elastography (VCTE/FibroScan):

• 8-15 kPa: Suggests F2-F3 fibrosis (moderate to advanced)
• 15-20 kPa: Likely advanced fibrosis; confirm with second NIT or imaging to exclude cirrhosis
• >20 kPa: Cirrhosis 3

Magnetic Resonance Elastography (MRE) (if available):

• 3.1-4.4 kPa: F2-F3 fibrosis
• 4.4-5.0 kPa: Advanced fibrosis; confirm cirrhosis status
• >5.0 kPa: Cirrhosis 3

Enhanced Liver Fibrosis (ELF) Test:

• 9.2-10.5: F2-F3 fibrosis
• 10.5-11.3: Advanced fibrosis; confirm cirrhosis status
• >11.3: Cirrhosis 3

Complete Diagnostic Workup in Secondary Care

Once referred to hepatology 1:

1. Detailed alcohol history using AUDIT-C questionnaire to exclude alcoholic liver disease
2. Complete liver etiology screen if not done in primary care:
   • Hepatitis B and C serology
   • Autoimmune markers (ANA, ASMA, immunoglobulins)
   • Iron studies (ferritin, transferrin saturation)
   • Ceruloplasmin (if age <40)
   • Alpha-1 antitrypsin level
3. Assess for drug-induced steatosis (amiodarone, methotrexate, tamoxifen, corticosteroids)
4. Metabolic profiling: Lipid panel, HbA1c, fasting glucose

When to Perform Liver Biopsy

Liver biopsy remains the gold standard for definitive NASH diagnosis but is not required for most patients 4, 3. Consider biopsy only in these specific scenarios 1:

• Diagnostic uncertainty when multiple liver diseases may coexist
• Inconclusive noninvasive staging with discordant results between tests
• Enrollment in clinical trials requiring histologic endpoints
• Consideration for NASH-specific pharmacotherapy (though the 2025 update suggests NITs are sufficient for semaglutide eligibility 3)

Critical pitfall: Biopsy has sampling error, is invasive, and carries risks. The trend is moving away from routine biopsy toward NIT-based management 3.

Surveillance and Monitoring

For Patients with Cirrhosis (F4)

• Hepatocellular carcinoma surveillance: Ultrasound ± AFP every 6 months
• Variceal screening: Upper endoscopy at diagnosis, then per gastroenterology guidelines
• Multidisciplinary management of metabolic comorbidities 1

For Patients with F2-F3 Fibrosis

• Candidates for semaglutide therapy (Wegovy® 2.4 mg weekly) if MASH with F2-F3 fibrosis 3
• Monitor treatment response at 72 weeks with:
  • ALT reduction >17 U/L or ≥20% suggests MASH resolution
  • VCTE reduction ≥30%, MRE ≥20%, or ELF ≥0.5 suggests fibrosis improvement 3

For Low-Risk Patients (F0-F1)

• Lifestyle modification remains cornerstone: target ≥7-10% weight loss through diet and exercise 4
• Optimize metabolic comorbidities: Diabetes control, lipid management, hypertension treatment
• Repeat FIB-4 every 3 years 1

Key Algorithmic Summary

1. Screen high-risk patients (T2DM, metabolic syndrome, incidental steatosis)
2. Calculate FIB-4 → Low risk: primary care management; Indeterminate: elastography; High risk: hepatology referral
3. In hepatology: Complete etiology screen + confirmatory elastography (VCTE/MRE/ELF)
4. Reserve biopsy for diagnostic uncertainty or trial enrollment only
5. If F2-F3 confirmed: Consider semaglutide; if cirrhosis: HCC surveillance + variceal screening
6. All patients: Intensive lifestyle modification + metabolic risk factor management

Common pitfall to avoid: Do not rely on ALT/AST levels to screen for or exclude NASH—they are normal in up to 50% of patients with significant fibrosis 1. Always use validated fibrosis scores.