Evaluation of gastrointestinal biopsies with two-slide serial sections: Analysis of 1715 cases with emphasis on clinical impact

Although serial sectioning may improve diagnostic yield, no standardized protocol currently exists for endoscopic gastrointestinal (GI) biopsies. The aim of this study was to determine whether examining two serially sectioned slides from each biopsy specimen increases the detection of clinically relevant histopathological findings. In this prospective study, 1715 endoscopic GI biopsy specimens were evaluated using a two-slide serial sectioning approach, with eight consecutive sections per slide. A diagnostic discrepancy was defined as the presence of a histopathological finding on one slide that was absent on the other, thereby representing slide-to-slide variability in detection. Each biopsy specimen was treated as an individual case for serial sectioning and diagnostic assessment purposes, regardless of patient identity, as the study focused on per-sample diagnostic variability. Diagnostic discrepancies between slides were found in 2.2 % of cases, with 1.4 % deemed clinically significant. These included both gain of additional findings on the second slide and loss of findings that were present only on the first slide. Intestinal metaplasia was the most frequently observed clinically relevant finding, particularly in antral biopsies. Importantly, no additional malignancies were identified on second slides, and none of the biopsy-related variables showed a significant association with diagnostic discrepancies. Overall, these findings suggest that, while infrequent, diagnostic discrepancies introduced by serial sectioning may have meaningful clinical implications—particularly in detecting preneoplastic conditions such as intestinal metaplasia in the antrum.