FibroScan®, sometimes called transient elastometry (TE) is a FDA approved non-invasive test to measure liver inflammation and fibrosis, (arguably) comparable to a liver biopsy, particularly in the higher end of the Metavir scale (Stages 3 and 4).
What is Metavir Grading System?
Several grading systems are used to determine "liver biopsy" results. The Metavir grading system uses two standardized numbers: one called "grade" to indicate degree of inflammation (tissue swelling and irritation) and the other called "stage" which indicates the degree of fibrosis (tissue scarring due to prolonged inflammation).
A 4-point scale is used in grading the degree of liver inflammation or histological activity:
- A0= no inflammation
- A1= mild inflammation
- A2= moderate inflammation
- A3= severe inflammation
A 5-point scale is used in grading the degree of liver fibrosis:
- F0= no fibrosis
- F1= minimal fibrosis
- F2= fibrosis has occurred and spread inside the areas of the liver including blood vessels
- F3= fibrosis is spreading and connecting to other liver areas that contain fibrosis
- F4= cirrhosis or advance liver fibrosis
Fibroscan scoring card
Keeping this in mind, we can use the Fibroscan scoring card to convert Fibroscan results measured in (kPa) into the Metavir scale F1-F4.
Located on the bottom of the Fibroscan scoring card is Fibroscan results in (kPa) measurements 0-75, more accurately Fibroscan results range from 2.5 kPa to 75 kPa. Between 90–95% of healthy people without liver disease will have a liver scarring measurement less then 7.0 kPa (median is 5.3 kPa).
A person with chronic hepatitis C and a liver stiffness more then 14 kPa has approximately a 90% probability of having cirrhosis, while patients with liver stiffness more then 7 kPa have around an 85% probability of at least significant fibrosis.
However, research has shown Fibroscan accuracy in assessing lower degrees of liver fibrosis (F1-F2) is not as reliable compared to diagnosing advanced fibrosis and cirrhosis (F3/F4)
Fibroscan Scoring Card
Two Examples of people with liver disease:
A fibroscan score of 8.2 in "hepatitis C " is the same as fibrosis stage 1-2 or (F1- F2) as shown in the color coded scale.
A fibroscan of 12.2 in a patient with "alcoholic liver disease" is borderline cirrhosis or (F3) .
FibroScan results - Fibrosis stage 1 and stage 4