Fibrosis-4 (FIB-4) Index for Liver Fibrosis
Noninvasive estimate of liver scarring in HCV and HBV patients, to assess need for biopsy.
When to Use
- Patients with any known risk factors for liver disease, including chronic hepatitis, alcoholic liver disease, non-alcoholic fatty liver disease (NAFLD) and the cholestatic and metabolic liver diseases.
- Patients with known liver fibrosis should have their fibrosis trended over time to evaluate for progression or stabilization.
- Liver fibrosis often progresses non-linearly, so it is important to be able to re-assess fibrosis trends in individual patients over time, and invasive re-assessments carry significant risk to patients. FIB-4 allows for non-invasive liver fibrosis assessment.
- FIB-4 was developed in patients with HIV and HCV co-infection.
- FIB-4 was developed to correlate with Ishak levels of fibrosis (by biopsy) with 3 levels:
- 0-2 (mild fibrosis)
- 3-4 (moderate fibrosis)
- 5-6 (severe fibrosis/cirrhosis)
- While liver biopsy is the gold standard for the diagnosis of liver fibrosis, it is not ideal; biopsy only evaluates a minute portion of the liver itself, so sampling errors can occur. Liver biopsy also comes with substantial morbidity.
- Liver fibrosis often progresses non-linearly, so it is important to be able to re-assess fibrosis trends in individual patients over time.
- It is critical that tests to identify liver cirrhosis are highly sensitive, as patients with the disease require screening for hepatocellular carcinoma (HCC) and gastroesophageal varices.
- The FIB-4 Index was shown to be superior to 7 other noninvasive markers of fibrosis in patients with NAFLD, including the NAFLD Fibrosis Score (Shah 2009).