TTP4.01 Liver Function Tests (LFTs): Predicting Gallstones in the Common Bile Duct – A Retrospective Cohort Study

Aim This study aimed to identify which LFTs best predict the presence of gallstones in the common bile duct (CBD). A secondary objective was to evaluate whether combining multiple LFTs improves positive predictive value (PPV). Methods A retrospective analysis was conducted on patients evaluated for gallstone disease at NHS Fife between April 2022 and April 2023. The sensitivity and PPV of individual and combination of LFTs for detecting CBD stones assessed using magnetic resonance cholangiopancreatography (MRCP). Results A total of 989 patients were reviewed. The PPVs for individual LFTs were: ALP (33.2%), ALT (32.9%), bilirubin (37.2%), and GGT (13.9%). When paired, the PPVs were: ALP & ALT (38.5%), ALP & Bili (43.2%), ALP & GGT (44.1%), ALT & Bili (41.5%), ALT & GGT (40.3%), and Bili & GGT (45.1%). Three-test combinations yielded PPVs of ALP/ALT/Bili (44.7%), ALP/ALT/GGT (47.9%), ALP/Bili/GGT (50.0%), and ALT/Bili/GGT (50.0%). Conclusions Relying on a single LFT has a lower positive predictive value than a combination of LFTs for the prediction of CBD stones.