Resource optimization in the examination of macroscopic normal colon mucosa

Background and study aims: Colonoscopy with biopsies is an essential procedure in the diagnostic workup of patients with chronic diarrhea. If the intestinal mucosa appears macroscopically normal or near-normal, tissue samples are retrieved from right and left segments of the colon and sometimes also from the ileum. Biopsies are sent to histological analysis in individual containers. The aim of this retrospective study was to examine whether the current procedure could be simplified by merging biopsies in one container without affecting the diagnostic quality. Patients/Materials and methods: Biopsies from patients with an endoscopically normal colon mucosa were included; 250 with a study diagnosis of microscopic colitis (MC) and 233 patients with a study diagnosis of non-MC. H&E-stained microscopy slides from the right and left colon were evaluated by two pathologists, and histological concordance between the right and left colon was determined. Results: In 232 (92.8%) patients with MC and 229 (98.3%) patients with non-MC, the diagnosis was identical in the right and left colon. In six patients from the MC group, biopsies from both segments were within the MC spectrum, while in 12 (4.5%) patients, the histological characteristics for MC were only fulfilled in one segment of the colon. Biopsies from the ileum were without clinical relevance. Conclusions: We suggest merging biopsies from the right and left colon of patients with macroscopically normal mucosa into a single container and refraining from obtaining ileal biopsies when MC is suspected, reducing resource consumption in the endoscopy unit and the pathology department. The results support a transition towards a more sustainable diagnostic procedure.