Routine White test for early

introductionBile leak (BL) remains one of the most common complications following liver resection, contributing to increased morbidity, prolonged hospitalisation and higher healthcare costs. Early intraoperative detection of open bile ducts is essential for minimising this risk. The intraoperative White test (WT), which involves retrograde injection of a lipid emulsion into the biliary tree, has been shown to enhance visualisation of BL and may reduce their incidence. However, the benefit of routine WT use across all types of liver resections has not been conclusively established. The Detection of Bile Leak in Elective Liver Resection (DELiveR) trial aims to evaluate the effectiveness and safety of routine intraoperative WT in elective liver surgery. METHODS AND ANALYSIS: This is a single-centre, prospective, parallel-group, participant-blinded and outcome assessor-blinded, superiority randomised clinical trial. Adult patients undergoing elective liver resection will be randomised in a 1:1 ratio to either routine WT using SMOFlipid 5% or standard intraoperative BL detection using visual inspection with white gauze. Final eligibility, including safe accessibility of an identifiable cystic duct or cystic duct stump for attempted cannulation, will be confirmed intraoperatively after completion of liver parenchymal transection and haemostasis. Eligible participants will then be randomised immediately before the assigned intraoperative BL assessment. The primary endpoint is the incidence of postoperative BL within 30 days, defined according to the International Study Group of Liver Surgery criteria. Permuted block randomisation will be used to allocate participants in a 1:1 ratio. The primary analysis will be conducted in the overall intention-to-treat population using logistic regression with treatment allocation as the independent variable. Secondary outcomes include severity of BL, postoperative morbidity and mortality, need for reinterventions, intensive care unit admission and length of hospital stay. A total of 270 patients will be enrolled. ETHICS AND DISSEMINATION: The study will be conducted in accordance with the Declaration of Helsinki and Good Clinical Practice guidelines. Ethical approval has been obtained from the Bioethics Committee of the Medical University of Warsaw. Written informed consent will be obtained from all participants. Study findings will be disseminated through peer-reviewed publications and presentations at national and international conferences. TRIAL REGISTRATION NUMBER: NCT07511907. PROTOCOL VERSION: DELiveR Trial Protocol, version 1.5, dated 28 August 2026.