How is a Fibroscan (Fibrosis Scan) of the liver interpreted?

How to Interpret FibroScan Results

FibroScan measures liver stiffness in kilopascals (kPa), with higher values indicating greater fibrosis severity, and interpretation requires both understanding the numerical thresholds and ensuring technical validity of the measurement. 1, 2

Technical Validity Requirements (Check These First)

Before interpreting any FibroScan result, verify the measurement meets all three reliability criteria 2:

• ≥10 successful measurements obtained
• Success rate ≥60%
• Interquartile range (IQR) <30% of the median value (or <15% when reported in m/s) 1

If these criteria are not met, the result is unreliable and should not be used for clinical decision-making 2. Failure rates are higher in Western populations (4.3-10.5%) compared to Asian populations (1.1-3.5%), primarily due to obesity 3.

Pre-Test Requirements

• Minimum 3-4 hours fasting is mandatory before testing 1
• Food ingestion falsely elevates liver stiffness values regardless of measurement method 1
• Earlier recommendations for 2 hours fasting were insufficient; studies show at least 3 hours are required for accurate measurements 1

Numerical Interpretation Thresholds

For NAFLD/MASLD:

• <8.0 kPa: Rules out advanced fibrosis (F0-F1, minimal or no fibrosis) with 93% sensitivity 2, 4
• 8.0-8.2 kPa: Threshold for significant fibrosis (≥F2) 2, 4
• 8-12 kPa: Advanced fibrosis (F3) 4
• >12.5 kPa: Cirrhosis (F4), requires urgent hepatology referral and HCC screening 2, 4

For Alcohol-Related Liver Disease:

• <8.0 kPa: Reliably rules out advanced fibrosis 2

For Chronic Viral Hepatitis (HBV/HCV):

• >7.0 kPa: Significant fibrosis (≥F2) 2
• >12.5 kPa: Cirrhosis 2
• FibroScan has 70%/84% sensitivity/specificity for significant fibrosis and 87%/91% for cirrhosis in viral hepatitis 2

For Portal Hypertension:

• >20 kPa: Esophageal varices are likely 5, 6
• >23.3 kPa: Predicts presence of at least grade 2 esophageal varices 6

Critical Confounding Factors That Falsely Elevate Results

Always exclude these conditions before interpreting FibroScan, as they cause overestimation of fibrosis 1:

• Active hepatic inflammation (acute hepatitis, ALT flares can produce falsely cirrhotic-range values) 1, 3
• Obstructive cholestasis (extrahepatic or intrahepatic) 1
• Right heart failure/venous congestion 1, 5
• Recent food ingestion (within 3-4 hours) 1
• Recent exercise 1
• Recent alcohol consumption (ideally test after 2 weeks of abstinence) 2
• Amyloidosis 1, 5
• Hepatic infiltration (tumor cells, mast cells, inflammatory cells) 5

Technical Limitations and When FibroScan Cannot Be Used

FibroScan is unreliable or impossible in 4, 7:

• Ascites (absolute contraindication)
• Severe obesity (BMI >28 kg/m², though XL probe may help) 3
• Narrow intercostal spaces
• Acute hepatitis
• Extrahepatic biliary tract obstruction

In the failure group, 93.9% of patients were overweight (BMI >25 kg/m²) 6. The XL probe produces values approximately 1.2-1.3 kPa lower than the standard M probe, requiring adjusted cutoffs 3.

Clinical Decision Algorithm Based on Results

If <8.0 kPa (Low Risk):

• Patient is at low risk for liver-related complications 2
• Repeat surveillance in 2-3 years if metabolic risk factors persist 2, 4
• Repeat in 3-5 years if risk factors well-controlled 2

If 8.0-12.0 kPa (Intermediate Risk):

• Significant fibrosis present (≥F2) 2, 4
• More aggressive management needed to prevent progression 7
• Consider hepatology referral depending on underlying disease 2
• Annual follow-up with non-invasive tools 4

If >12.0-12.5 kPa (High Risk):

• Cirrhosis present - requires urgent hepatology referral 2, 4
• Initiate HCC screening (ultrasound every 6 months) 2
• Evaluate for portal hypertension and esophageal varices 2, 5
• Consider liver biopsy or additional testing 7

Integration with Other Tests

Sequential testing using FIB-4 followed by FibroScan for indeterminate scores is more accurate than either test alone 4, 7:

• Calculate FIB-4 first in all adults with chronic liver disease 2
• FIB-4 <1.3 (<2.0 if age >65): Low risk, repeat in 1-3 years 7
• FIB-4 1.3-2.67: Indeterminate, proceed to FibroScan 7
• FIB-4 >2.67: High risk, refer to hepatology regardless of FibroScan 2

Common Pitfalls to Avoid

• Do not rely on FibroScan alone - it only measures stiffness, not inflammation or alternative diagnoses 2
• Suboptimal accuracy for mild-moderate fibrosis - cannot adequately discriminate between adjacent fibrosis stages 1
• ALT is a major confounding factor in chronic hepatitis B - use higher cutoff values when ALT is elevated up to 5x upper limit of normal 3
• 18-43% of patients with normal ALT may have significant fibrosis, particularly those >35-40 years old 4
• Liver biopsy may still be needed when non-invasive tests show discordant results or concurrent liver diseases are suspected 4

Disease-Specific Considerations

For chronic hepatitis B, use an ALT-based algorithm with higher cutoffs when ALT is elevated 3. For NAFLD, the optimal cutoff for F≥F2 is 8.2 kPa (rounded to 8.0 kPa clinically) 2, 4. For autoimmune hepatitis, optimal cutoffs are 6.27 kPa for F2, 8.18 kPa for F3, and 12.67 kPa for F4 8.