Precision Pathology: Unveiling the role of Interval Sectioning Protocol for Optimal Diagnosis in Pancreatic, Ampullary, and Bile Duct Biopsies

Abstract Introduction/Objective Endoscopic techniques offer advanced diagnostics but encounter challenges in obtaining limited pancreaticobiliary biopsies, including ampullary (AMP), EUS-guided pancreatic (PAN), and spy bite biliary (BD) biopsies. Interval sectioning optimizes immunohistochemical stain utility and tissue conservation. This study evaluates interval sectioning protocols’ impact on diagnostic precision and tissue preservation at our institution. Methods/Case Report This analysis examines cases over four months before and after a protocol change, focusing on AMP, BD, and PAN biopsies. Previously, AMP and BD biopsies used three H&E-stained slides, while PAN required two H&E-stained and five unstained slides (USS). The new protocol adopts seven slides with H&E staining on levels 1, 4, and 7, emphasizing consistency. Parameters assessed include diagnosis, turnaround time (TAT), and USS utilization. A 30% USS utilization cutoff justifies upfront interval sectioning. Results (if a Case Study enter NA) A total of 77 cases from the old protocol and 142 from the new protocol were reviewed. No significant difference in TAT between old and new protocols was found (p=0.340). However, PAN TAT notably improved (4848 min vs. 2932 min). Usage rates varied by site: 22.2% (AMP), 33.3% (BD), and 34.4% (PAN). Conclusion USS usage was lowest for AMP cases (22.2%), below the 30% threshold for upfront interval sectioning justification. Eliminating interval sectioning for AMP would save 116 USS in the new protocol. BD and PAN cases warrant upfront interval sectioning, with USS usage rates of 31.5% and 33.7%, respectively. While PAN cases show no cost difference, the new protocol improves specimen visualization, correlates immunohistochemical stains better, and significantly enhances turnaround time.