*5.1.2.5 Detection of immunogenic gluten peptides in human samples*

Recently, new noninvasive methodologies have been developed to monitor gluten exposure in patients with CD based on the detection and quantification of GIP in stool and urine samples [87–90]. These immunological methodologies (ELISA and immunochromatographic strips) based on G12 and A1 moAbs are capable of detecting GIP, which are gluten fragments resistant to gastrointestinal digestion, and mainly responsible for the immune response of patients with CD [60, 61, 91–95]. These tools make it possible to monitor adherence to GFD and detect violations cases, helping to identify the origin of clinical symptoms and avoid complications derived from gluten intake (anemia, osteoporosis, increased risk of lymphoma, etc.). These techniques have represented a revolutionary worldwide advance in the clinical practice of CD and have been introduced in the new guidelines, both European and Spanish, for monitoring the GFD of patients with CD [1, 41]. Numerous rigorous studies have evaluated the use of GIP determination in stool and/or urine to monitor adherence to GFD compared to other tools (**Table 2**). The studies included children and adults diagnosed with CD and healthy volunteers. Overall, these studies indicated that this novel technique was highly sensitive for the detection of GFD transgressions and therefore could facilitate the follow-up of patients with CD.
