How to interpret a FibroScan (Fibrosis Scan) test result?

How to Interpret a FibroScan (Transient Elastography) Test Result

FibroScan results should be interpreted based on established cutoff values measured in kilopascals (kPa), with <8.0 kPa indicating minimal fibrosis, 8.0-12.0 kPa suggesting significant fibrosis, and >12.0 kPa indicating advanced fibrosis or cirrhosis. 1

Understanding FibroScan Measurements

FibroScan (transient elastography) is a non-invasive tool that measures liver stiffness to assess the degree of fibrosis. The results are reported in kilopascals (kPa) and correspond to different stages of liver fibrosis:

• <8.0 kPa: Low risk for clinically significant fibrosis (F0-F1); recommended surveillance testing in 2-3 years 1
• 8.0-12.0 kPa: Intermediate risk, suggesting significant fibrosis (≥F2-F3) 1
• >12.0 kPa: High risk for advanced fibrosis or cirrhosis (F3-F4); referral to hepatology recommended 1

Technical Considerations for Valid Results

For reliable FibroScan interpretation, ensure:

• At least 10 successful measurements were obtained 2, 3
• Success rate is at least 60% of attempted measurements 2, 3
• Interquartile range (IQR) is less than 30% of the median value 1, 3
• Patient fasted for at least 4 hours before the test (postprandial state can falsely increase readings) 1, 4

Disease-Specific Interpretation

Different liver diseases may require slightly different cutoff values:

Chronic Hepatitis C

• F2 (significant fibrosis): >7.0 kPa 1
• F3 (advanced fibrosis): 10.0 kPa 1
• F4 (cirrhosis): >13.0 kPa 1

Non-alcoholic Fatty Liver Disease (NAFLD)

• F2 (significant fibrosis): 8.2 kPa (rounded to 8.0 kPa for clinical use) 1, 2
• F3-F4 (advanced fibrosis/cirrhosis): >12.0 kPa 1

Autoimmune Hepatitis

• F2: 6.27 kPa 5
• F3: 8.18 kPa 5
• F4: 12.67 kPa 5

Factors That May Affect Results

Be aware of factors that can lead to falsely elevated readings:

• Acute hepatitis or significant inflammation (elevated ALT) 1, 6
• Recent food intake (postprandial state) 1, 4
• Right heart failure or liver congestion 1
• Extrahepatic cholestasis 1, 6
• Obesity (consider using XL probe for BMI >30) 6

Clinical Application Algorithm

1. Initial Assessment:

   • Begin with simple fibrosis scores like FIB-4 or APRI for initial risk stratification 1, 2
   • FIB-4 <1.3 reliably excludes advanced fibrosis 2
   • FIB-4 >2.67 indicates high risk for advanced fibrosis 2

2. Sequential Testing:

   • For patients with indeterminate FIB-4 scores (1.3-2.67), proceed to FibroScan 1, 2
   • Sequential testing using FIB-4 followed by FibroScan is more accurate than either test alone 1, 3

3. Result Interpretation:

   • <8.0 kPa: Low risk, monitor with repeat testing in 2-3 years 1
   • 8.0-12.0 kPa: Intermediate risk, consider more frequent monitoring (annually) 3

   • 12.0 kPa: High risk, refer to hepatology for consideration of liver biopsy or additional testing 1

4. Follow-up Recommendations:

   • Consider repeating FibroScan after 6 months in patients with borderline elevated values to confirm results 4
   • Weight loss of ≥1 kg can significantly reduce liver stiffness measurements 4
   • Increased physical activity can also improve liver stiffness measurements 4

Common Pitfalls to Avoid

• Relying on a single measurement when values are borderline (8-12 kPa) 4
• Failing to account for ALT levels when interpreting results 1, 6
• Not considering the prevalence of advanced fibrosis in the target population when interpreting results 1
• Using inappropriate cutoffs for specific liver diseases 1, 5, 7
• Interpreting results without considering clinical context and other laboratory findings 8