What is the appropriate workup and management for an 11‑year‑old girl with a positive deamidated gliadin peptide (DGP) antibody suggesting celiac disease?

Workup and Management for Positive Deamidated Gliadin Peptide Antibody in an 11-Year-Old Girl

This child requires immediate measurement of tissue transglutaminase IgA (tTG-IgA) antibodies with total serum IgA level, and if tTG-IgA is positive, proceed to small bowel biopsy for diagnostic confirmation before initiating any dietary changes. 1

Initial Diagnostic Workup

Complete the Serologic Panel

• Measure tTG-IgA antibodies with total serum IgA level as the primary diagnostic test, since tTG-IgA has superior sensitivity (90-96%) and specificity (>95%) compared to deamidated gliadin peptide (DGP) antibodies alone 2

• If total IgA is deficient, measure IgG-based tests (IgG tTG or IgG endomysial antibodies) instead, as IgA-based tests will be falsely negative 3

• Do not rely on isolated positive DGP antibodies for diagnosis, as research shows an isolated positive DGP with normal tTG has only a 2.5% positive predictive value for celiac disease in children 4

Critical Caveat About DGP Testing

The evidence reveals an important limitation: DGP antibodies have poor specificity (26-79%) and should not be used as a standalone screening test 5, 6. In one multicenter study, 148 children were tTG-negative but DGP-positive, yet only 5% (8/148) actually had villous atrophy on biopsy 5. This means isolated positive DGP results lead to many unnecessary biopsies.

However, there are two specific scenarios where DGP adds value:

• Children under 2 years of age, where DGP may detect cases missed by tTG alone 7
• IgA-deficient patients, where IgG DGP can identify celiac disease when IgA-based tests are unreliable 3, 6

Confirmatory Testing

Duodenal Biopsy Indications

• If tTG-IgA is positive, perform esophagogastroduodenoscopy with duodenal biopsies to confirm diagnosis before establishing dietary changes 3, 1

• Obtain four oriented biopsies from the second portion of the duodenum plus two oriented biopsies from the bulb for adequate histologic assessment 8

• European guidelines suggest biopsy may be avoided only in symptomatic children with tTG-IgA titers >10 times the upper limit of normal AND positive endomysial antibodies on a separate blood sample, but this approach is not universally adopted 1

HLA Typing

• Consider HLA-DQ2/DQ8 testing if serologic results are equivocal or if the patient has already started a gluten-free diet, as negative HLA testing effectively rules out celiac disease 3

Pre-Diagnostic Considerations

Maintain Gluten in Diet

• The child must remain on a gluten-containing diet (at least three slices of wheat bread daily) until all testing is complete, as gluten avoidance reduces sensitivity of both serology and biopsy 3, 2

• If the patient has already reduced gluten intake, resume normal gluten consumption for 1-3 months before repeat testing 3

Review Medication History

• Obtain thorough medication history, particularly for angiotensin II receptor blockers like olmesartan, which can cause villous atrophy mimicking celiac disease 3

Management if Celiac Disease is Confirmed

Immediate Referral and Baseline Testing

• Refer immediately to a dietitian experienced in both celiac disease and pediatric nutrition for gluten-free diet counseling 1

• Test for micronutrient deficiencies including iron, folate, vitamin D, and vitamin B12, which are common at diagnosis 1

• Document baseline growth parameters (height and weight) as these are essential markers of treatment success in children 3, 1

Gluten-Free Diet Implementation

• Strictly avoid all products containing wheat, barley, and rye proteins for life 1

• Pure oats may be introduced slowly with careful monitoring for adverse reactions, though they are generally safe for most children with celiac disease 1

Follow-Up Schedule

• Schedule follow-up visits at 6 months, 12 months, then annually thereafter to monitor adherence and disease activity 1, 8

• Repeat tTG-IgA antibodies at each visit to assess dietary adherence, though negative serology does not guarantee mucosal healing 8

• Monitor growth parameters closely at each visit, as satisfactory increases in weight and height are essential markers of successful treatment in children and adolescents 3

• Routine vitamin and mineral testing is unnecessary in children who attend regular follow-up and grow normally without symptoms 3

Special Consideration for Adolescents

Be aware that this 11-year-old is approaching adolescence, a period when adherence typically declines 3, 8. Teenagers are less satisfied with the impact of celiac disease on their lives and are less adherent to gluten-free diets 3. Children lost to follow-up are more frequently non-adherent and antibody-positive 3. Therefore, establish close follow-up early and provide age-appropriate counseling about the importance of dietary adherence to prevent long-term complications including malabsorption, anemia, and osteoporosis 3.