Celiac disease is common and affects approximately 0.7 to 1% of the population. Due to its protean manifestations, celiac serology is often requested for chronic non-febrile ailments for which there is no obvious cause.
Tricore Laboratories routinely performs total serum IgA levels, anti-deamidated gliadin IgA antibody and tissue transglutaminase IgA antibody (tTG) levels when a celiac serology is requested.
Past studies have shown that tTG is very sensitive and specific ‘screening’ test for the diagnosis of celiac disease. Additionally, the same studies show that positive anti-gliadin antibody in the presence of negative tTG antibody levels suggests the former to be a false positive result.
In the last 18 months, the UNM Division of Pediatric Gastroenterology has seen 8 children with positive anti-gliadin antibody and negative tTG antibody levels while they were consuming gluten. All were planned for endoscopy in the setting of ongoing gastrointestinal symptoms, though, for various reasons, only 3 children have had an EGD. Of these, 2 have shown features of eosinophilic esophagitis without evidence of celiac disease, and the third with normal biopsy results.
These results support that positive anti-gliadin antibody in the presence of negative tTG antibody levels suggests that the likelihood of celiac disease is very low, though may be indicative of other conditions such as eosinophilic esophagitis. Therefore, in the presence of a negative tTG, a positive anti-gliadin antibody should be considered a false positive test for celiac disease, though still may be indicative of other gastrointestinal conditions.
A more comprehensive 10-year retrospective study is planned. This is the first report to our knowledge of this observation.
Hessinger, Justin and Pankaj Vohra. "Implications of Positive Anti-Gliadin Antibody with Negative Tissue Transglutaminase Antibody Titers While Consuming Gluten." (2021). https://digitalrepository.unm.edu/hsc_2021_pediatric_research/7