Do persistently low positive TGA-IgA levels predict celiac disease?

Repeated low or moderate anti– transglutaminase immunoglobulin A (TGA-IgA) values are indeed associated with a celiac disease (CD) diagnosis, a study in symptomatic children showed. Participants in the Italian study had repeated serum IgA and TGA-IgA tests along with testing for endomysial antibodies (EMAs) and human leukocyte antigens, as well as esophagogastroduodenoscopy (EGD). Of 281 children, 224 had at least 2 positive TGA-IgA determinations, whereas in 57, the second test was negative. All the children followed a normal gluten-containing diet while awaiting results of the EGD and biopsies. Participants were divided into 3 groups based on TGA-IgA values: group A (low positive), group B (moderate positive), and group C (controls). Of 162 children in group A, 142 (87.7%) received a CD diagnosis, but normal duodenal mucosa was found in 20 children. In group B, all 62 children received a CD diagnosis. Given these results, investigators concluded that symptomatic children with persistently low positive TGA-IgA levels should undergo EGD, regardless of their EMA status.

Thoughts from Dr. Farber

This is not an uncommon clinical dilemma—does one perform an invasive and expensive test when screening results are unclear? The answer in this case is yes. But remember, we are talking about children who had some symptoms and whose tests were not negative, just not markedly positive.

Reference

1. Trovato CM, Montuori M, Morelli A, et al. Diagnostic value of persistently low positive TGA-IgA titers in symptomatic children with suspected celiac disease. J Pediatr Gastroenterol Nutr. 2021;72(5):712-717. doi:10.1097/ mpg.0000000000003047