Which Screening Tool Is Ineffective for Pediatric Celiac Disease?

Deamidated gliadin peptide (DGP) immunoglobulin G (IgG) testing does not effectively differentiate between children with and without celiac disease, according to a new study. In turn, the researchers say that DGP IgG testing should not be a part of the initial screening for celiac disease among the pediatric population.

While tissue transglutaminase antibodies are the most established serological test for celiac disease, the use of newer DGP screening tests is increasing. However, there has been no systematic study on the incidence of celiac disease in children with an isolated positive DGP result.

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To determine the positive predictive value of DGP serology for biopsy-confirmed celiac disease in pediatric patients with elevated DGP and normal transglutaminase, the researchers analyzed data on children from birth to aged 18 years with isolated DGP IgG positive serology who had visited 1 of 3 centers in Canada.

The researchers calculated the positive predictive value of an isolated elevated DGP result of each participant.

In all, 40 participants with DGP positive, transglutaminase negative serology underwent endoscopy with duodenal biopsy with only 1 participant—who was immunoglobulin A (IgA) deficient—having biopsy-confirmed celiac disease.

This means there is a positive predictive value of 2.5% for isolated DGP IgG positive serology.

“In isolation, DGP positive serology has a poor positive predictive value for celiac disease in children, especially in IgA sufficient individuals,” the researchers concluded. “Further research is needed to clarify to role of DGP IgG in children under the age of 2 and those with IgA deficiency.”

—Colleen Murphy

Reference:

Gould MJ, Brill H, Marcon MA, Munn NJ, Walsh CM. In screening for celiac disease, deamidated gliadin rarely predicts disease when tissue transglutaminase is normal. J Pediatr Gastroenterol Nutr. 2019;68(1):20-25. doi: 10.1097/MPG.0000000000002109.