Given the high prevalence of NAFLD, patient management by specialists is not feasible. As such, screening for increased risk of advanced fibrosis is essential for triaging NAFLD patients for specialist care and better management. To this end, LifeLabs has introduced the Fibrosis-4 (FIB-4) index and the Enhanced Liver Fibrosis (ELF™) score.
Fibrosis-4 (FIB-4) Index*
The FIB-4 index is a simple and inexpensive marker that is calculated from aspartate aminotransferase (AST), alanine aminotransferase (ALT), platelet count and age. Recently, the American Association of Clinical Endocrinology (AACE) recommended using FIB-4 as the preferred initial test to assess the risk of fibrosis in NAFLD patients. A FIB-4 score of <1.30 showed high negative predictive value for the identification of advanced fibrosis, whereas a score of >2.67 showed high positive predictive value. Importantly, using FIB-4 index with these threshold values was estimated to save 78% of liver biopsies in the cases evaluated.
*Please note that currently, the FIB-4 Index is only available in Ontario
Enhanced Liver Fibrosis (ELF™) Score*
The ELF™ Score is also a simple, accurate, non-invasive blood test that measures the levels of tissue inhibitor of metalloproteinases 1, amino-terminal propeptide of type III procollagen, and hyaluronic acid. ELF™ is used to estimate the rate of liver extracellular matrix metabolism which reflects the severity of liver fibrosis and the risk of progression to cirrhosis and other liver-related clinical events.
The AACE recently recommended ELF™ as a second level test for the screening of liver fibrosis in high-risk patients with intermediate or high FIB-4 index results. FIB-4 together with ELF™ can be used in a two-step pathway in primary care to assess the risk of severe liver fibrosis and for risk stratification and triaging of patients for specialist care. Using both tests in this way was shown to significantly reduce the number of unnecessary biopsies.
In absence of FIB-4, patients with persistently elevated ALT or AST levels and/or indeterminate or high-risk ELF™ Scores can be referred to a gastroenterologist or hepatologist for further assessment. Results should always be interpreted in conjunction with the patient’s medical history, clinical presentation, and other findings.
*Please note that the ELF™ Score is not currently available in BC but will be introduced later this year