What is the role of Fibroscan (Fibrosis Scan) in diagnosing liver fibrosis?

FibroScan in Diagnosing Liver Fibrosis

FibroScan (vibration-controlled transient elastography) is a validated, non-invasive tool that should be used as a second-line test after initial risk stratification with simple serum scores (FIB-4 or NFS) to identify advanced fibrosis in patients with chronic liver disease, avoiding liver biopsy in most cases. 1

Diagnostic Pathway: When to Order FibroScan

Step 1: Initial Risk Stratification

• Always calculate FIB-4 first using routine labs (age, AST, ALT, platelet count) in all adults with suspected chronic liver disease 1, 2, 3
• FIB-4 <1.3 (or <2.0 if age >65 years) reliably excludes advanced fibrosis with ≥90% negative predictive value—no FibroScan needed 4, 3
• FIB-4 >2.67 indicates high risk for advanced fibrosis (60-80% positive predictive value)—refer directly to hepatology 4, 3
• FIB-4 between 1.3-2.67 is the primary indication for FibroScan 1, 4, 3

Step 2: Disease-Specific Indications for FibroScan

For NAFLD/Metabolic Liver Disease:

• Use FibroScan for patients with indeterminate FIB-4 scores (1.3-2.67) or NAFLD Fibrosis Score (-1.455 to 0.675) 1, 3
• Patients with metabolic syndrome, obesity, or diabetes warrant FibroScan if initial scores are indeterminate 1, 2

For Alcohol-Related Liver Disease:

• FibroScan should be ordered earlier in the pathway for patients drinking at harmful levels (≥35 units/week for women, ≥50 units/week for men) 3
• Cutoff <8.0 kPa reliably rules out advanced fibrosis 1, 3
• Critical pitfall: Avoid testing during active drinking—wait 2 weeks after abstinence, as recent alcohol falsely elevates liver stiffness 3

For Chronic Viral Hepatitis (HBV/HCV):

• Use FibroScan for staging fibrosis to guide treatment decisions 3
• APRI >0.5 or FibroScan >7.0 kPa identifies significant fibrosis (≥F2) 3
• APRI >1.0 or FibroScan >12.5 kPa identifies cirrhosis 3

Diagnostic Performance and Interpretation

Fibrosis Stage Cutoffs

• Mild fibrosis (F0-F1): <8.0 kPa 2
• Significant fibrosis (≥F2): >7.0 kPa 2, 4
• Advanced fibrosis (F3): 8-12 kPa 2
• Cirrhosis (F4): >12.5 kPa 2, 3

Accuracy Data

The most recent guideline evidence shows FibroScan has excellent diagnostic performance 1:

• AUROC 0.93 for detecting advanced fibrosis in NAFLD (95% CI 0.86-0.96) 1
• Optimal cutoff 9.9 kPa with 95% sensitivity and 77% specificity for advanced fibrosis 1
• AUROC 0.88-0.90 for identifying advanced fibrosis across liver diseases 1

Important nuance: The AASLD 2018 guideline notes that 27% of participants had unreliable results in U.S. cohorts, while Japanese studies showed 10.5% failure rates—obesity significantly impacts technical success 1

Technical Validity Requirements

A FibroScan result is only reliable if ALL three criteria are met 2, 3:

1. ≥10 successful measurements obtained
2. Success rate ≥60%
3. Interquartile range <30% of median value

Common technical limitations that invalidate results 1, 2, 4:

• Ascites
• Severe obesity (though XL probe improves success)
• Narrow intercostal spaces
• Acute hepatitis (falsely elevates stiffness)
• Extrahepatic biliary obstruction
• Recent food intake within 2-3 hours

Clinical Decision-Making Based on Results

Low-Risk Results (LSM <8.0 kPa)

• Repeat surveillance testing in 2-3 years if risk factors remain 2, 4
• Continue addressing underlying liver disease (lifestyle modification, antiviral therapy) 2

Intermediate Results (LSM 8.0-12.0 kPa)

• Annual monitoring recommended 2
• More frequent monitoring (every 6-12 months) if multiple risk factors present, borderline values (7-8 kPa), or elevated liver enzymes 2

High-Risk Results (LSM >12.5 kPa)

• Urgent hepatology referral required 3
• Initiate hepatocellular carcinoma screening 3
• Consider liver biopsy if concurrent liver diseases suspected 2

Advantages Over Liver Biopsy

FibroScan should replace liver biopsy for routine fibrosis assessment because 1, 2:

• Liver biopsy has 25-60% discordance between samples from the same patient due to sampling error 4
• Biopsy carries 0.33% mortality risk and up to 30% experience significant pain 1
• FibroScan is rapid (5 minutes), provides immediate results, and can be repeated for serial monitoring 1, 2, 5
• Sequential testing (FIB-4 followed by FibroScan) is more accurate than either test alone 2, 4

When Liver Biopsy Is Still Needed

Consider biopsy in these specific scenarios 1, 2:

• Discordant results between FibroScan and serum markers
• Suspicion of concurrent liver diseases that cannot be excluded non-invasively
• Need for histologic grading of inflammation or steatosis to guide treatment
• Patients at high risk for steatohepatitis requiring definitive diagnosis

Critical Pitfall to Avoid

18-43% of patients with normal ALT levels may have significant fibrosis, particularly those older than 35-40 years 2—do not rely on normal liver enzymes to exclude the need for fibrosis assessment in high-risk populations (metabolic syndrome, harmful alcohol use, viral hepatitis) 1, 2