*5.1.2.3 Intestinal biopsy*

Histological lesion remains the gold standard test for the diagnosis of CD, recovery of the mucosa is the main marker of response to diet. The only method to verify this normalization of the duodenum is by performing an oral endoscopy with an intestinal biopsy, an aggressive and costly follow-up method. However, an intestinal biopsy is a method used clinically, especially in the evaluation of patients with persistent symptoms [81]. It seems advisable to perform a follow-up endoscopy in adults

1–2 years after starting GFD to ensure recovery of the mucosa [82]. In this way, it would be possible to differentiate patients who are at low risk and in whom follow-up periods can be extended, from those at high risk who may need special supervision to maintain adherence to GFD [83].
