Over the past decades, the American Joint Committee on Cancer (AJCC) has established a well-defined system for cancer staging based on 3 key components: local tumor extent (T stage), dissemination to the regional lymph nodes (N stage), and metastatic spread to distant sites (M stage) (TNM staging).¹ The AJCC TNM staging system attempts to use anatomical and reproducible parameters to discriminate groups with different survival outcomes.^1-4 Reliable prediction of survival estimates is of paramount importance in cancer care. Accurate prognostication helps clinicians in guiding treatment decisions, provides researchers with a tool to adjust for cancer stage in evaluating treatment outcomes, and is informative to patients themselves.^5,6

The Enhanced Liver Fibrosis (ELF) test is a non-invasive biomarker, suggested as an appropriate test for advanced liver fibrosis in non-alcoholic fatty liver disease (NAFLD). This systematic review aimed to provide summary estimates of the accuracy of this test against biopsy. In this systematic review, we searched MEDLINE, Embase, Web of Science and the Cochrane Library, for studies included NAFLD patients and undertook both liver biopsy as the reference standard and the ELF test. Two authors independently screened the references, extracted the data and assessed the quality of included studies. Due to the variation in reported thresholds, we used a multiple thresholds random effects model for meta-analysis (diagmeta R-package). The meta-analysis of 11 studies reporting advanced fibrosis and five studies reporting significant fibrosis showed sensitivity of >0.90 of the ELF test for excluding fibrosis at threshold of 7.7. However, as a diagnostic test at high thresholds, the test showed specificity and positive predictive value >0.80, only in very high-prevalence settings (>50%). Desiring specificity of 0.90 for advanced and significant fibrosis resulted in thresholds of 10.18 (sensitivity: 0.57) and 9.86 (sensitivity: 0.55), respectively. The ELF test showed high sensitivity but limited specificity to exclude advanced and significant fibrosis at low cutoffs. The diagnostic performance of the test at higher thresholds was found to be more limited in low prevalence settings. We conclude that clinicians should carefully consider the likely disease prevalence in their practice setting and adopt suitable test thresholds to achieve the desired test performance.