Objectives: This study examines the prevalence of detectable gluten immunogenic peptides (GIPs) as a proxy for gluten exposure in children with celiac disease on a gluten-free diet in the United States, as estimated by gluten breakdown products excreted in urine and stool. Methods: Urine and stool samples were collected in 3 settings (home, gastroenterology clinic, and endoscopy) for pediatric participants (ages 6–21 years old) across 2 medical centers. Commercial ELISA assays were used to quantify the GIPs in each sample. Results: GIPs were detected in 4 out of 44 (9.1%) of stool samples and 6 out of 125 (4.8%) of urine samples provided by 84 children. These samples were collected across all settings, and most participants (70%) were asymptomatic at the time of sample collection. For the urine samples collected at the time of endoscopy, all subjects found to have persistent enteropathy had no detectable GIPs (0/12). Discussion: GIPs provide an additional method for screening for gluten exposures in individuals with celiac disease on a gluten-free diet, and may be used across multiple settings. We found a low detection rate of GIPs in children. Our finding of undetectable GIPs in individuals with persistent enteropathy may be expected of a single determination under close observation or represent a lack of gluten exposure within the detection window. More research is needed to understand the dynamics of gluten absorption and excretion in the US pediatric population.

Studies involving human intestinal tissue are essential for advancing the field of celiac disease (CeD), as diagnosis requires duodenal biopsies. Performing studies in children helps to better understand CeD in this important subpopulation. This study aims to determine the risk in obtaining duodenal research biopsies during pediatric endoscopy. In this retrospective chart review from 2016 to 2022 of 1180 research subjects and controls, there were 18 procedure-related adverse events within 48 hours. Most adverse events were for symptoms of pain and fever. There was no increased risk of adverse events if additional duodenal research biopsies were taken during pediatric endoscopy.