Duodenal bulb histological analysis should be standard of care when evaluating celiac disease in children.

We confirmed the added value provided by sampling D1 in the diagnosis of CD in comparison to the diagnosis yield when only the more distal duodenum (D2, D3, and/or D4) was sampled. The severity of CD, as assessed by the Marsh-Oberhuber classification, did not increase distally; on the contrary, in 39/60 (65%) of the cohort, the features of CD were either more severe or only present in D1.