Complementary Roles of PCT, CRP, WBC, and ΔWBC in Early Leak Detection after Bariatric Surgery: A Retrospective Pilot Study

Introduction: Postoperative leakage is a critical complication after bariatric surgery, necessitating early and accurate detection. Conventional markers like C-reactive protein (CRP) and white blood cell (WBC) counts are often limited by low specificity due to nonspecific inflammatory responses. Procalcitonin (PCT), a marker more specific to bacterial infections, may improve diagnostic reliability. This study compared the diagnostic performance of PCT with CRP, WBC, and ΔWBC (postoperative–preoperative difference) to enhance postoperative surveillance. Methods We retrospectively analyzed 579 bariatric surgery patients. Diagnostic performance was assessed using sensitivity, specificity, likelihood ratios, and confidence intervals. Group comparisons used the Kruskal–Wallis and Fisher’s exact tests. Spearman’s rank correlation examined associations with clinical variables. Hospital stay and complication rates were also evaluated under a PCT-centered protocol. Results PCT showed the highest specificity (98.4%) compared to CRP (94.3%) and WBC (67.7%), though sensitivity was limited (33.3%) due to the low incidence of leaks (n = 3). PCT remained specific in one anastomosis gastric bypass (OAGB), whereas CRP and WBC were influenced by baseline inflammation. In revision surgeries, specificity declined across all markers, but ΔWBC retained strong performance (92%). The PCT-based protocol was associated with shorter hospital stays (22.0 vs. 25.0 hours, p < 0.001) without increased complication rates. Conclusion PCT is a highly specific early marker for complications after bariatric surgery. When combined with conventional markers, particularly ΔWBC, it may support more efficient patient management. Further validation in broader clinical settings is warranted.