When is it possible to get false positive screening results for celiac disease?

Abstract

Goals. Determine the causes of overdiagnosis of gluten dependent conditions, based on the level of antibodies (AT) to transglutaminase (tTG) IgA and total IgA, which have high sensitivity and specificity.
Materials and methods. We enrolled patients with an increased level of TG2 antibodies (average level — 45.64 ± 11.3 IU/ml), examined at the Clinical Center for the period 2020–2021. The total number of patients with positive re4sults was 61, up to 4 years old — 49 patients, 12 children — over 10 years old.
Results. Complaints typical for gastrointestinal tract pathology were present in less than 1/3 of cases (most often, abdominal distension — 18/29.6%). Among the extra- gastrointestinal manifestations, complaint that is more common was poor appetite — 46/75.4% (with normal level of physical development) and the presence of allergic manifestations in the form of atopic dermatitis — 35/57.4%. We re-monitoring the level of TG2 antibodies after 3 months (children were on a regular diet). It was shown that in 56 patients the level of TG2 were within the normal range. 5 patients with the exacerbation of the allergic process had the level of TG2 1.5 times higher than normal, followed by normalization as the skin manifestations fade away.
Conclusions. As a result of screening for celiac disease with testing of TG2 antibodies, false- positive results were detected in 1.6% of cases with negative tests for antibodies to endomysium. According to our data, the most common reasons for false positive results were the presence of an allergic pathology in the acute stage, an acute intestinal infection and parasitic infections.