Clinical utility of serum Mac-2 binding protein glycosylation isomer as a noninvasive marker for liver fibrosis in biliary atresia.

BACKGROUND: Hepatic fibrosis influences treatment decisions and clinical outcomes in biliary atresia (BA). As liver biopsy is invasive and unsuitable for serial assessments, noninvasive biomarkers are required. This study aimed to evaluate serum Mac-2 binding protein glycosylation isomer (M2BPGi) as a noninvasive biomarker by assessing its correlation with histopathologic fibrosis in children with BA. METHODS: This prospective, exploratory diagnostic accuracy study enrolled 135 children who were assigned to one of the following three groups: BA with liver transplantation, BA with Kasai portoenterostomy, and choledochal cysts (control group). Intraoperative tissue was staged using METAVIR (stages F0-F4). The preoperative M2BPGi level and aspartate aminotransferase-to-platelet ratio index, Fibrosis-4 index, and S-index were compared across stages using receiver-operating characteristic (ROC) analysis with Youden-derived cutoffs. RESULTS: M2BPGi increased progressively with fibrosis stage and outperformed all comparators. M2BPGi discriminated advanced fibrosis (stage ≥F3) (area under the ROC curve [AUC], 0.953) and cirrhosis (stage F4) (AUC, 0.986). The optimal Youden-derived cutoff index (COI) of 3.02 showed strong performance (stage ≥F3: 87.8% sensitivity and 96.5% specificity; F4: 97.6% sensitivity and 93.6% specificity). A rule-out COI threshold of 0.81 achieved 100% sensitivity and a negative predictive value for stage ≥F3. CONCLUSION: M2BPGi is an accurate noninvasive biomarker for hepatic fibrosis in BA that may support clinical decision-making regarding fibrosis surveillance and transplantation timing.