Background Detection of gluten immunogenic peptides (GIP) is a potential objective biomarker of adherence to gluten-free diet (GFD). As current methods require specialized laboratories, we evaluated novel point-of-care (POC) kits for GIP detection in stool and urine. Methods Ten children with Crohn’s disease followed a 3-week GFD, after 8 weeks of exclusive enteral nutrition (EEN). 78 stool and urine samples were collected; one before EEN completion, six during the GFD, and one after return to unrestricted diet. Single samples were collected from 17 healthy adults after a 7-day EEN. Stool GIP was measured with reference ELISA (S-REF) and POC (S-POC) kits; urine GIP with POC kits (U-POC). Results Non-adherence to GFD was detected in 8/10 patients using S-REF, compared to 2/10 patients using conventional dietary assessment. Substantial inter-class agreement was noted between S-REF and S-POC (88% concordance, kappa = 0.74). Lower GIP levels, measured with S-REF, were seen in discordant compared to positive concordant samples. The optimal S-POC detection threshold was 0.11 mg/kg (sensitivity: 100%, specificity: 91%, p < 0.001). Agreement between S-REF and U-POC was lower (concordance: 73%, kappa = 0.39). Conclusions The S-POC kit is a suitable alternative for GIP detection, demonstrating high sensitivity and specificity except at very low GIP levels. Detection of GIP in urine is less accurate. Impact <UnorderedList Mark="Bullet"> <ItemContent> Detection of gluten immunogenic peptides (GIP) offers a promising objective biomarker for monitoring adherence to gluten-free diets. However, current methods require specialized labs and long processing times. </ItemContent> <ItemContent> By measuring GIP in stool, we identified children with Crohn’s disease who were non-adherent despite standard assessments indicating otherwise. </ItemContent> <ItemContent> A point-of-care GIP kit demonstrated high sensitivity and specificity in detecting GIP in stool making it a potential alternative to the reference ELISA method. In contrast, GIP detection using urine kits was suboptimal. </ItemContent> <ItemContent> Our study supports the potential clinical utility of bedside point-of-care GIP kits that may improve treatment adherence and efficacy of gluten-free-diets. </ItemContent> </UnorderedList>

Comparing urine and stool gluten immunogenic peptides for detecting compliance to gluten-free diets

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2025年7月24日

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Konstantinos Gkikas,
Laura Gianolio,
Miles Kavanagh,
Bernadette White,
Caroline Kerbiriou,
Maria Lima,
Vaios Svolos,
Richard Hansen,
Richard K. Russell,
Konstantinos Gerasimidis

摘要

Background

Detection of gluten immunogenic peptides (GIP) is a potential objective biomarker of adherence to gluten-free diet (GFD). As current methods require specialized laboratories, we evaluated novel point-of-care (POC) kits for GIP detection in stool and urine.

Methods

Ten children with Crohn’s disease followed a 3-week GFD, after 8 weeks of exclusive enteral nutrition (EEN). 78 stool and urine samples were collected; one before EEN completion, six during the GFD, and one after return to unrestricted diet. Single samples were collected from 17 healthy adults after a 7-day EEN. Stool GIP was measured with reference ELISA (S-REF) and POC (S-POC) kits; urine GIP with POC kits (U-POC).

Results

Non-adherence to GFD was detected in 8/10 patients using S-REF, compared to 2/10 patients using conventional dietary assessment. Substantial inter-class agreement was noted between S-REF and S-POC (88% concordance, kappa = 0.74). Lower GIP levels, measured with S-REF, were seen in discordant compared to positive concordant samples. The optimal S-POC detection threshold was 0.11 mg/kg (sensitivity: 100%, specificity: 91%, p < 0.001). Agreement between S-REF and U-POC was lower (concordance: 73%, kappa = 0.39).

Conclusions

The S-POC kit is a suitable alternative for GIP detection, demonstrating high sensitivity and specificity except at very low GIP levels. Detection of GIP in urine is less accurate.

Impact

Detection of gluten immunogenic peptides (GIP) offers a promising objective biomarker for monitoring adherence to gluten-free diets. However, current methods require specialized labs and long processing times.

By measuring GIP in stool, we identified children with Crohn’s disease who were non-adherent despite standard assessments indicating otherwise.

A point-of-care GIP kit demonstrated high sensitivity and specificity in detecting GIP in stool making it a potential alternative to the reference ELISA method. In contrast, GIP detection using urine kits was suboptimal.

Our study supports the potential clinical utility of bedside point-of-care GIP kits that may improve treatment adherence and efficacy of gluten-free-diets.