Duodenal biopsies for coeliac disease: does size matter?

Background/Objectives: Most adult patients require endoscopy and duodenal biopsies to diagnose coeliac disease. However, individuals who are unwilling or unable to undergo conventional endoscopy are left without diagnostic options or a formal diagnosis. We aimed to determine whether the small-sized biopsy forceps used during the more tolerable transnasal endoscopy (TNE) can provide adequate duodenal biopsy specimens for diagnosing coeliac disease. Methods: We prospectively recruited adult patients (≥18 years) with suspected coeliac disease between May and July 2024. All patients underwent peroral endoscopy, with four biopsies taken from the second part of the duodenum (D2) and one from the duodenal bulb (D1) using standard 2.8 mm biopsy forceps. The biopsy protocol was then repeated using smaller 2 mm biopsy forceps. Expert pathologists evaluated all samples for size, quality, and Marsh classification. Results: Ten patients (median age 45 years, 50% female) were included in this study, of whom seven (70%) were diagnosed with coeliac disease. In total, 100 duodenal biopsy specimens were collected and analysed (50 using standard biopsy forceps and 50 using smaller biopsy forceps). The size of D2 biopsies was significantly larger when using standard biopsy forceps compared with smaller forceps (4.5 mm vs. 3 mm, p = 0.001). Similarly, biopsies from D1 were also larger with standard forceps (3 mm vs. 2 mm, p = 0.002). Smaller forceps provided sufficient material for accurate classification in all cases, and the agreement between biopsies obtained using both forceps in D2 and D1 was 100% (k = 1.0). Conclusions: This pilot study demonstrates that small-sized biopsy forceps, used during TNE, can provide adequate tissue for histopathological diagnosis in patients with suspected coeliac disease. These findings pave the way for considering TNE as a more tolerable alternative to conventional endoscopy in diagnosing coeliac disease.