Specific antibodies along with a duodenal biopsy allow a secure diagnosis of celiac disease. Case detection rates have improved but many patients remain undiagnosed. The only treatment available at present is the gluten-free diet (GFD) to include gluten-free oats (requires monitoring because of rare reactions to oat avenin). Most respond clinically to a GFD but histologic recovery is not always complete and may result in clinical consequences.
The best initial serology test for diagnosis in suspected celiac disease is the tissue transglutaminase (TTG) IgA antibody. This includes children aged less than 2 years. A total IgA level appropriate for age is required to interpret a negative TTG IgA test. In those with IgA deficiency, the deamidated gliadin peptide and/or TTG IgG antibody may be helpful for diagnosis along with a duodenal biopsy. Active case finding (homozygous DQ2 girls of a first-degree relative at highest risk) has increased the detection of celiac disease though it is an imperfect strategy. Mass screening would increase detection rates in asymptomatic individuals but benefit versus harm for this strategy is unknown because of a lack of understanding of latent-to-declared disease and management.
courtesy University of Chicago
Dr. Carol Semrad
Both serology and duodenal biopsy have pitfalls in the diagnosis of celiac disease. In children, the diagnosis of celiac disease is secure when a TTG IgA antibody is greater than 10 times positive along with a positive confirmatory endomysial antibody on another day without a duodenal biopsy. All others require biopsy for diagnosis. There is less data on the correlation of a TTG IgA antibody greater than 10 times positive with villous atrophy in adults. Considerations to forgo biopsy in adults when TTG IgA is greater than 10 times positive include those who already started a GFD based on serology, unable to undergo endoscopy with duodenal biopsy, or with a shared decision to forgo biopsy.
Clinical response to a GFD and antibody conversion to negative are criteria used to assess for celiac disease recovery. However, antibody conversion to negative does not always correlate with histology. Clinical consequences of persistent villous atrophy include increased risks for lymphoproliferative malignancy, hip fracture, and refractory celiac disease. Data is lacking for or against follow up duodenal biopsy for mucosal healing and requires an individualized discussion with consideration when 2 years or more on a GFD unless ongoing symptoms warrant an earlier biopsy.
Dr. Semrad is director of the small bowel disease and nutrition program at the University of Chicago Medicine where she is a professor of medicine. She disclosed no conflicts of interest.
References
Rubio-Tapia et al. Am J Gastroenterol. 2023;118:59-76.
Husby S et al. J Pediatr Gastroenterol Nutr. 2020;70:141-57.
