No-biopsy Approach in Celiac Disease: Cut-off Points for IgA Anti-tissue Transglutaminase Assays

The main objective of this multicenter and observational study is to define the optimal threshold of different commercially available IgA anti-transglutaminase (tTG-IgA) antibody assays for celiac disease diagnosis (CD) avoiding the need for an intestinal biopsy. The main questions to be answered are: * Is the anti-tTG-IgA titer cut-off above 10 times the upper limit of normal (ULN) useful in all anti-tTG IgA assays? * Is the diagnostic performance of the newly defined cut-offs of anti-tTG-IgA the same in all the evaluated assays? * Is the dynamic of the anti-tTG-IgA levels after the introduction of the gluten-free diet (GFD) similar across the different assays included in the study? This is a prospective multicenter study that will enroll pediatric and adult patients with new-onset CD during the years 2023 and 2024. Serum from these patients will be collected for the determination of anti-tTG-IgA according to the local methodology (participating hospital) and by the anti-tTG IgA assays most commonly used in our country, which will be centralized in the same reference center (Hospital Universitario La Paz).

NCT Number	NCT05983978
Lead Sponsor	Instituto de Investigación Hospital Universitario La Paz Collaborators: Hospital Mutua de Terrassa, Hospital Sant Joan de Deu, Hospital Universitario Ramon y Cajal, Hospital Universitario Lucus Augusti, Hospital Universitario Fundación Jiménez Díaz, Instituto de Investigación Sanitaria Hospital Clínico San Carlos
Conditions	Celiac Disease
Enrollment	150 participants
Start Date	2023-01-02
Primary Completion	2026-03-31 (estimated)
Study Completion	2026-03-31 (estimated)
Updated on ClinicalTrials.gov	2025-08-06