Protocol for a diagnostic accuracy study to develop diagnosis algorithm for biliary atresia using MMP-7 (DIABA-7 study): a study recruiting from Chinese Biliary Atresia Collaborative Network

Introduction Biliary atresia is a severe liver disease in neonates, and the prognosis partially depends on the age at which infants undergo the Kasai procedure. Matrix metalloproteinase-7 (MMP-7) was confirmed to have significant value in the diagnosis of biliary atresia. However, so far, the reference range and its cut-off value for diagnosing biliary atresia have not been established yet. Methods and analysis DIagnosis Algorithm for Biliary Atresia (DIABA-7) is a prospective diagnostic test. Cholestatic infants and normal controls within 150 days of age are recruiting from the Chinese Biliary Atresia Collaborative Network. The serum samples and dried blood spot (DBS) samples are obtained to detect MMP-7 concentrations using an ELISA kit. The reference standard is the intraoperative exploration and subsequent histological examination of liver biopsies. Lambda-Mu-Sigma (LMS) method is used to calculate the normal range of serum MMP-7 of each age group. Receiver operating characteristics (ROC) curves are constructed to calculate the best cut-off point and area under the curve for the index test. The sensitivity, specificity, positive predictive value and negative predictive value are used to show the diagnostic accuracy. Pearson correlation coefficient test is applied to assess the correlation of serum MMP-7 and DBS MMP-7. Ethics and dissemination This study was reviewed and approved by the Ethics Committee of Children’s Hospital of Fudan University (Number 2020–296). Dissemination will be guided by investigators and patients. The aim is to publish the study results in a high-quality peer-reviewed journal and present the findings at international academic meetings. Trial registration number ChiCTR2000032983.