Gluten immunogenic peptide excretion detects dietary transgressions in treated celiac disease patients

Table 4 Celiac serology, dietary adherence assessed by dietary report and gluten immunogenic peptide excretion tests in samples from patients with celiac disease not responding to the gluten-free diet (symptomatic cases)

Patient No.	Serology		First set of determinations				Second set of determinations
	IgAtTG AU/mL	IgADGPAU/mL	Dietary report	GIP in stool ELISA μg/g	GIP in stool PoCT	GIP in urine PoCT	Dietary report	GIP in stool ELISA μg/g	GIP in stool PoCT	GIP in urine PoCT
1	3	5	Strict	< 0.16	ND	ND	NA	< 0.16	-ve	ND
2	15	9	NA	< 0.16	ND	ND	Strict	< 0.16	ND	ND
3	30	75	Strict	0.38	ND	ND	Strict	< 0.16	ND	-ve
4	77	> 200	NA	< 0.16	-ve	-ve	NA	< 0.16	-ve	-ve
5	8	1	Strict	< 0.16	-ve	-ve	Strict	< 0.16	-ve	-ve
6	4	6	Strict	< 0.16	-ve	-ve	NA	< 0.16	-ve	-ve
7	3	13	Strict	< 0.16	-ve	-ve	Strict	< 0.16	-ve	-ve
8	27	11	Strict	ND	ND	-ve	Strict	< 0.16	-ve	-ve
9	3	39	Strict	< 0.16	ND	-ve	Strict	< 0.16	-ve	-ve
10	5	4	Strict	< 0.16	-ve	-ve	Strict	< 0.16	-ve	-ve
11	> 200	67	Strict	< 0.16	-ve	-ve	Strict	0.42	-ve	-ve
12	8	10	Strict	< 0.16	-ve	-ve	Strict	< 0.16	-ve	-ve
13	3	35	NA	< 0.16	-ve	-ve	Strict	< 0.16	+ve	-ve
14	ND	ND	NA	< 0.16	-ve	-ve	NA	< 0.16	-ve	-ve
15	12	12	Strict	< 0.16	-ve	-ve	Strict	< 0.16	-ve	-ve
16	14	25	Strict	< 0.16	-ve	-ve	ND	ND	ND	ND
17	8	9	Strict	< 0.16	-ve	-ve	ND	ND	ND	ND
18	17	36	Strict	< 0.16	-ve	-ve	Strict	< 0.16	-ve	-ve
19	8	24	NA	< 0.16	-ve	-ve	Strict	< 0.16	-ve	-ve

Dietary assessments were categorized as “strict” (patients with no transgression detected) or no adherence (by sources: transgression by foods with potential gluten sources or by traces: patients with potential intake of gluten traces). Gluten immunogenic peptides in stool by enzyme-linked immunosorbent assay< 0.156: no gluten excretion detected. NA: No adherence; ND: Not determined and excluded from analysis; –ve: Negative result; +ve: Positive result; DGP: Deamidated gliadin peptide; GIP: Gluten immunogenic peptides; ELISA: Enzyme-linked immunosorbent assay; PoCT: Point-of-care test.