{
  "abstract": "Introduction Duodenal biopsy remains the diagnostic gold standard for adult coeliac disease (CD under current British Society of Gastroenterology (BSG) guidelines. During the COVID-19 pandemic, interim BSG guidance allowed a non-biopsy diagnostic pathway for selected symptomatic adults under 55 years with anti-tissue transglutaminase (tTG) titres greater than ten times the upper limit of normal (ULN). More recently, the 2025 European Society for the Study of Coeliac Disease guidelines have conditionally supported a similar approach for adults under 45 years. However, there is no clear post-pandemic consensus in UK practice. As a result, increasing reliance on serology alone has been observed, often outside strict eligibility criteria. This assumes a high specificity of elevated tTG titres, despite evidence that raised titres may occur in non-coeliac enteropathies. This study aimed to assess local adherence to diagnostic protocols and evaluate the risk of misdiagnosis when biopsy is omitted. 1Methods A retrospective cohort analysis was performed on 163 adults (≥18 years) with positive coeliac serology identified in 2023. tTG titres were analysed and compared between patients with histologically confirmed coeliac disease and those with non-coeliac histology. The degree of serological overlap was assessed to evaluate the safety of relying on tTG titres alone for diagnosis.Results Elevated tTG titres were not exclusive to patients with histologically confirmed coeliac disease. Among patients with non-coeliac histology, tTG values showed a right-skewed distribution (median 24.0 IU/ml, mean 34.2 IU/ml). Although 75% of these patients had titres below 49.5 IU/ml, significant outliers were identified. Notably, some patients with normal duodenal histology had tTG titres as high as 128.0 IU/ml. These findings demonstrate substantial overlap in tTG values between coeliac and non-coeliac patients, including titres that exceed thresholds commonly used to justify a non-biopsy diagnosis.The overlap shows why tTG alone cannot replace a biopsy. Non-coeliac patients can still present with surprisingly high titres.Conclusion This study raises concerns regarding the safety of non-biopsy diagnosis in adults. The existence of non-coeliac patients with tTG titres reaching 128 IU/ml levels that mimic ‘clear-cut’ coeliac disease, demonstrates that serology cannot reliably replace histological confirmation. Patients without villous atrophy may present with titres that appear diagnostic, risking incorrect diagnosis and unnecessary lifelong dietary restriction. Duodenal biopsy therefore remains essential to ensure diagnostic accuracy in adult coeliac disease.References Al-Toma A, Zingone F, Branchi F, et al. European Society for the Study of Coeliac Disease 2025 updated guidelines on the diagnosis and management of coeliac disease in adults. Part 1: Diagnostic approach. United European Gastroenterol J. 2025;13(8):1–19.Srinivasa A, Bendall O, Babikir A, et al. British Society of Gastroenterology, Association of Upper Gastrointestinal Surgery of Great Britain and Ireland and Royal College of Pathologists Delphi consensus guidance on biopsy sampling during upper gastrointestinal endoscopy in adult patients. Frontline Gastroenterology. Published Online First: 12 November 2025. doi: 10.1136/flgastro-2025-103316Abstract FP54 Figure 1The serology ‘danger zone’",
  "authors": [
    {
      "affiliations": [
        "Countess of Chester Hospital NHS Foundation Trust, Chester, United Kingdom"
      ],
      "name": "Malik Satea El Atrash"
    },
    {
      "affiliations": [
        "Countess of Chester Hospital NHS Foundation Trust, Chester, United Kingdom"
      ],
      "name": "Robin Augustine"
    },
    {
      "affiliations": [
        "Countess of Chester Hospital NHS Foundation Trust, Chester, United Kingdom"
      ],
      "name": "Jun Shang Poon"
    },
    {
      "affiliations": [
        "Countess of Chester Hospital NHS Foundation Trust, Chester, United Kingdom"
      ],
      "name": "Michael Davies"
    }
  ],
  "title": "FP54 The serology trap: why biopsy remains non-negotiable in adult coeliac disease",
  "uid": "781a2a75-0363-54fc-9b24-599ce3cd5da1"
}