Overview of noninvasive assessment of liver fibrosis

Noninvasive tests for liver fibrosis are now routinely used in clinical practice to determine the stage of liver disease, provide prognostic information, and guide treatment decisions. Noninvasive tests have dramatically reduced the need for liver biopsy and have the advantage of being able to be performed repeatedly, therefore providing a dynamic assessment of the progression of chronic liver disease.

The majority of noninvasive tests were developed for use and initially validated in patients with chronic viral hepatitis. Vibration-controlled transient elastography (VCTE) with FibroScan is the most well-validated noninvasive test.

Noninvasive tests are correlated with histological stages of liver fibrosis, which are scored from F0 (no fibrosis) to F4 (cirrhosis). In addition to being able to identify if a patient has minimal fibrosis (F0–F1) or cirrhosis, the intermediate stages of F2 (significant fibrosis) or F3 (advanced fibrosis) are also important to guide treatment decisions in some types of liver disease.

Noninvasive tests are generally more accurate for diagnosis of cirrhosis than for differentiating between intermediate stages of fibrosis. However, some tests have been developed specifically to detect advanced fibrosis; for example, the NAFLD Fibrosis Score. Most noninvasive tests are better at ruling out diagnoses (high negative predictive value) than confirming them.

Noninvasive tests consist of:

• tests for liver fibrosis based on serum markers
• measurement of liver stiffness.

For principles of interpreting noninvasive tests for liver fibrosis, see here.