4–8 Recently, transient elastography (TE) using FibroScan (EchoSens, Paris, France) was introduced as a promising non-invasive device for assessing liver fibrosis, and it has shown considerable accuracy for predicting cirrhosis in patients with chronic viral hepatitis.9–11 For a better prediction of liver fibrosis, some studies suggested Vismodegib chemical structure the combined use of TE, serologic fibrosis markers, and demographic and serologic biochemical variables.12–14 In the current issue of the Journal

of Gastroenterology and Hepatology, Lee et al.13 proposed a new fibrosis prediction formula, called the HALF index, which incorporated serum haptoglobin, apolipoprotein A1, α-2 macroglobulin, and TE as constituent variables. The superiority of the HALF index was proved by internal validation. The authors demonstrated that the area under the receiver–operator characteristic curve (AUROC) of the HALF index for predicting significant

fibrosis (≥F2) was 0.915 (95% confidence ICG-001 order interval: 0.868–0.949), which was significantly higher than the AUROC of TE alone (AUROC: 0.877; 95% confidence interval: 0.825–0.918; P = 0.010). However, as the confidence intervals of the HALF index and TE overlap, the statistical significance is questionable. Thus, the clinical applicability of the HALF index needs an independent external validation with a large sample size. In general, most non-invasive serologic fibrosis markers, formulae, and TE or TE-based prediction models are better at predicting liver cirrhosis than “significant fibrosis.” Interestingly, the AUROC of the HALF index for predicting significant fibrosis was higher than that for predicting liver cirrhosis (0.915 vs 0.892) in

the study of Lee et al.,13 albeit minimally, whereas the AUROC of TE remained similar (0.877 vs 0.878). In a further analysis, the study population was stratified into two groups according to their serum ALT levels (high- and low-ALT groups) to check the influence of necroinflammation Teicoplanin on the HALF index, which includes TE as a constituent factor. Importantly, the HALF index was not influenced by a high ALT, whereas the performance of TE increased significantly in the low ALT group, compatible with other reported findings. Conclusively, all these data indicate that the HALF index can predict significant fibrosis accurately, possibly better than TE, free of the influence of a high ALT in causing unreliable estimations of liver fibrosis. Therefore, if the HALF model can be validated sufficiently, it would be a useful tool for detecting significant fibrosis in patients with chronic viral hepatitis and for deciding when to start antiviral treatment. When we interpret the results of cross-sectional studies on non-invasive fibrosis prediction models, several issues should be considered.