Retrospective assessment of current "no-biopsy" diagnostic criteria in Celiac disease patients diagnosed by endoscopic biopsy

Although histopathological evaluation of samples obtained via upper gastrointestinal endoscopy remains the gold standard diagnostic method in celiac disease (CD), according to the diagnostic criteria updated in 2020 by the European Society for Pediatric Gastroenterology, Hepatology, and Nutrition (ESPGHAN), in patients suspected of CD, a serum anti-tissue transglutaminase (tTG) IgA level more than 10 times the upper limit of normal (ULN) and a positive anti-endomysial antibody test in a second serum sample are considered sufficient for diagnosis without biopsy. In this study, the validity of "no-biopsy" diagnostic criteria was retrospectively evaluated in CD patients who were diagnosed via endoscopy between January 1, 2004, and September 30, 2022, at the Department of Pediatric Gastroenterology, Hacettepe University Faculty of Medicine. Out of the 701 patients included in the study, 421 (60.1%) were female, 280 (39.9%) were male, with an average age of 8 years 5 months at the time of endoscopy. Among the 472 CD patients who could be evaluated according to the ESPGHAN 2020 "no-biopsy" approach 382 (80.9%) met the criteria. The sensitivity of the ESPGHAN 2020 "no-biopsy" approach was found to be 80.9%, specificity 97.0%, positive predictive value (PPV) 98.7%, and negative predictive value (NPV) 64.0%. Anti-tTG IgA levels ≥10×ULN alone provided 82.5% sensitivity, 95.6% specificity, 98.2% PPV, and 65.7% NPV for the diagnosis of CD. The optimal cut-off value of anti-tTG IgA for predicting CD was calculated as 5.15xULN (sensitivity 90.2%, specificity 89.6%, PPV 96.1%, and NPV 76.2%). A statistically significant correlation was observed between increasing levels of anti-tTG IgA and the severity of histological findings (p<0.001). In our center, endoscopy could have been avoided in 4 out of every 5 patients diagnosed via endoscopy by using "no-biopsy" approach. In conclusion, this thesis demonstrated that high anti-tTG IgA titers (particularly ≥10×ULN) reliably predict villous atrophy and CD, supporting the safe use of ESPGHAN 2020 "no-biopsy" approach in CD diagnosis. Keywords: Celiac disease, esophagogastroduodenoscopy, endoscopic biopsy, anti tissue transglutaminase antibody, no-biops approach