287 Beig J, et al. Frontline Gastroenterology 2022;13:287–294. doi:10.1136/fgastro-2020-101728 Original research Is duodenal biopsy always necessary for the diagnosis of coeliac disease in adult patients with high anti- tissue transglutaminase (TTG) antibody titres? Junaid Beig , 1 Kamran Rostami, 2 David T S Hayman , 3 Summer Hassan, 1 Stephen Gerred, 1 Ravinder Ogra 1 Small bowel and nutrition To cite: Beig J, Rostami K, Hayman DTS, et al. Frontline Gastroenterology 2022;13:287–294. ► Additional supplemental material is published online only. To view, please visit the journal online (http://dx.doi. org/10.1136/fgastro-2020- 101728). 1 Gastroenterology and Hepatology, Middlemore Hospital - Counties Manukau DIstrict Health Board (CMDH), Auckland, New Zealand 2 Gastroenterology and Hepatology, MidCentral District Health Board, Palmerston North, New Zealand 3 Molecular Epidemiology and Public Health Laboratory, School of Veterinary Science, Massey University, Palmerston North, New Zealand Correspondence to Dr Junaid Beig, Gastroenterology and Hepatology, Waikato District Health Board, Hamilton, New Zealand; drjunaidyaseen@gmail. com Received 13 February 2021 Accepted 8 June 2021 Published Online First 25 June 2021 © Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ. ABSTRACT Objective Avoiding duodenal biopsy in adults for coeliac disease (CD) diagnosis is controversial. Some retrospective and prospective studies have shown that CD can be reliably diagnosed in adults with serology rather than duodenal biopsies. This study aimed to check the accuracy of a cut-off value of ≥10 upper limit of normal of anti-tissue transglutaminase antibody (anti-TTG IgA) titres for CD diagnosis in adult patients. Method We retrospectively analysed adult patients (≥16 years) who underwent gastroscopy from 2013 to 2018 for positive coeliac serology. The relationship between titres and disease was determined by using linear models, whereas sensitivity and specifcity were assessed by receiver operator curve. Results We analysed 144 newly anti-TTG antibody-positive adult patients with a median age of 48.5 years (IQR 32–62); among them, 86 (60%) patients had CD (Marsh III: n=68 and Marsh II and I: n=18) with a higher prevalence in females (n=59 (69%)) and Europeans (n=60 (70%)). Fifty (58%) patients with CD had colonoscopy and fve (6%) had imaging; only six patients were diagnosed with additional conditions. An anti-TTG IgA titre cut-off value of 150 U/L was 100% specifc for CD in our dataset, with 70% (95% CI: 60% to 88%) sensitivity for this patient group. Conclusion Coeliac serology using anti-TTG IgA with titres ≥10× normal value is an excellent predictor of CD, irrespective of age, gender and ethnicity. Duodenal biopsy may not be necessary in selected adult patients with CD, especially younger than 50 years of age without additional gastrointestinal red-fag signs and symptoms. INTRODUCTION Coeliac disease (CD) prevalence world- wide is about 1.4% based on serolog- ical testing and 0.7% based on biopsy Summary box What is already known on this subject? ⇒ A ‘no duodenal biopsy’ approach’ is well established in paediatric guidelines for diagnosing coeliac disease (CD). A 10-fold increase in anti-tissue transglutaminase antibody (anti-TTG IgA) levels with anti-endomysial antibody positivity is sufficient to make a diagnosis of CD in the absence of duodenal biopsies. CD diagnosis without duodenal biopsy is deemed controversial in adults because of concerns about missing life-threatening concomitant diseases despite limited evidence for this. What are the new fndings? ⇒ Apart from showing that anti-TTG IgA titres of ≥10 times the ULN excellent specificity at detecting CD, we also showed that the presence of life- threatening concomitant disease was rare. How might it impact on clinical practice in the foreseeable future? ⇒ The findings of this study support the approach of serology-based diagnosis of CD in patients without red-flag signs and symptoms. This approach has significant clinical practice implications in the current scenario of the COVID-19 pandemic. It may help to reduce unnecessary procedures and reduce the wait time of more urgent cases in a stressed healthcare system.