Advantages and limitations of non-invasive tests for the diagnosis of non-alcoholic fatty liver disease


Non-alcoholic fatty liver disease (NAFLD) is among the most common chronic liver disorders worldwide and can sometimes lead to serious conditions like cirrhosis and hepatocellular carcinoma. As such, early assessment of the severity of NAFLD is essential for prompt intervention. Non-alcoholic steatohepatitis (NASH) and liver fibrosis are two important factors that determine the progression of NAFLD and the likelihood of developing cirrhosis, respectively. Until now, liver biopsy has been the most widely recognized method for diagnosing and evaluating NASH and fibrosis. However, it is an invasive procedure that is susceptible to observer bias and suboptimal standardization.

Therefore, recent studies have focused on exploring non-invasive tests for NAFLD, NASH and fibrosis, for clinical applications. Now, Chinese researchers have compiled recent developments in NAFLD assessment and analyzed the advantages and limitations of the new methods in a review posted online in January 2022 and subsequently published on March 5, 2022, in Volume 135, Issue 5 of Chinese medical journal.

Accumulating evidence points to different non-invasive tests for diagnosing NAFLD, assessing its severity, and predicting its prognosis. We have reviewed recent literature and summarized the key features of each test.

Teacher. Vincent Wai-Sun Wong, corresponding author of the study

The team clarifies that there are two main types of non-invasive testing; blood biomarker tests and imaging methods. Blood tests, with multi-biomarker panels, can measure and assess biological processes in the liver with decent accuracy. They may be useful for the initial diagnosis of liver disorders, as they are more accessible and economical compared to imaging methods. For example, the Fibrosis Index-4 and the Enhanced Liver Fibrosis Panel are promising biomarker tests for detecting advanced fibrosis and predicting its progression. However, some of these tests are influenced by age and gender and have limited effectiveness in staging liver disorders.

Imaging methods have proven to be more accurate in detecting and assessing the severity of liver disorders. For example, magnetic resonance imaging proton density fat fraction detects NAFLD and NASH with high accuracy, and also stratifies NASH severity. Similarly, machine learning-based ultrasound imaging is gaining popularity to effectively detect and quantify NAFLD. Imaging techniques such as transient elastography, acoustic radiation force pulse, and magnetic resonance elastography can accurately measure liver stiffness, which is an indicator of fibrosis. However, these methods are often expensive, have limited availability, lack widespread validation, and may require experienced operators.

Ultimately, the selection of appropriate tests to assess liver disorders is contextual. Availability, cost, and local expertise are key factors to consider when establishing a clinical care pathway for NAFLD“, observes Dr. Wong.

The authors suggest that further research is needed to determine the effectiveness of these testing methods in different clinical settings and to assess their importance in identifying patients in need of treatment and monitoring treatment response. However, having a plethora of options isn’t always a bad thing when it comes to staying one step ahead of critical illnesses.


Journal reference:

Li, G. et al. (2022) Noninvasive testing for nonalcoholic fatty liver disease. Chinese medical journal.


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