Principles of interpreting noninvasive tests for liver fibrosis

When interpreting noninvasive test results, consider:

• the type of test used and reproducibility of results
• the reliability of the test measurements obtained (including factors that may influence the test, and technical issues)
• diagnostic accuracy of the test and cut-off values for the type of liver disease being assessed
• the histological fibrosis stage that the noninvasive test is designed to predict
• correlation of the test result with clinical features and results of other diagnostic tests.

The same testing modality should be used when comparing multiple results for a patient. Results from different test modalities should not be directly compared. However, concordance of two or more different noninvasive modalities can improve overall diagnostic accuracy, as does the sequential use of noninvasive tests in algorithms (for example, this may be used when assessing for fibrosis in nonalcoholic fatty liver disease).

If a noninvasive test result is not diagnostic, or two different test results are not concordant, consider referral to a liver specialist for consideration of liver biopsy.

There are no validated noninvasive tests of fibrosis regression, so these tests should not be used to make management decisions related to regression. Specifically, noninvasive tests should not be used to make the decision to stop surveillance for hepatocellular carcinoma after treatment of chronic viral hepatitis.