While tissue transglutaminase (tTG) antibodies are the most established serological test for celiac disease, newer deamidated gliadin peptide (DGP) screening tests are increasingly being completed. No pediatric study has systematically assessed the incidence of celiac disease in patients with an isolated positive DGP result. We sought to determine the positive predictive value of DGP serology for biopsy-confirmed celiac disease in pediatric patients with elevated DGP and normal tTG, to help guide clinicians’ decision making when screening for this common condition and avoid unnecessary invasive follow-up diagnostic testing.
A multicenter retrospective review of children, from birth to age 18, with isolated DGP immunoglobulin G (IgG) positive serology referred to 3 Canadian centers was completed. The positive predictive value of an isolated elevated DGP result was calculated.
Forty patients with DGP positive, tTG negative serology underwent endoscopy with duodenal biopsy. Of these, only 1 patient had biopsy-confirmed celiac disease. This patient was IgA deficient. This yields a positive predictive value of 2.5% (95% confidence interval 0.1%–14.7%) for isolated DGP IgG positive serology.
In isolation, DGP positive serology has a poor positive predictive value for celiac disease in children, especially in IgA sufficient individuals. Our findings suggest that DGP IgG testing should not be completed as part of the initial screening for celiac disease in the pediatric population as it does not effectively differentiate between individuals with and without the disease. Further research is needed to clarify to role of DGP IgG in children under the age of 2 and those with IgA deficiency.
*Department of Paediatrics, University of Toronto
†Department of Paediatrics, McMaster University
‡Department of Paediatrics, William Osler Health System
§Division of Gastroenterology & Nutrition, McMaster Children's Hospital
||Division of Gastroenterology, Hepatology and Nutrition, Hospital for Sick Children
¶Michael G. DeGroote School of Medicine
#Department of Family Medicine, McMaster University
**The Research and Learning Institutes, Hospital for Sick Children
††The Wilson Centre, University of Toronto, Toronto, Ontario, Canada.
Address correspondence and reprint requests to Catharine M. Walsh, MD, MEd, PhD, FRCPC, FAAP, The Wilson Centre and the Division of Gastroenterology, Hepatology and Nutrition, the Learning and Research Institutes, Hospital for Sick Children, Department of Paediatrics, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada M5G 1X8 (e-mail: firstname.lastname@example.org).
Received 16 March, 2018
Accepted 3 July, 2018
C.M.W. holds a Career Development Award from the Canadian Child Health Clinician Scientist Program.
No funding organization had any role in the design and conduct of the study, collection, management, analysis, and interpretation of the data; and preparation, review, or approval of the manuscript.
Previous presentations: The abstract of an earlier version of this article was presented as an oral presentation at the 2017 NASPGHAN Annual Meeting.
The authors report no conflicts of interest.