Testing and Treatment for Celiac Disease
The diagnostic approach for celiac disease should begin with serological testing using IgA tissue transglutaminase antibody (tTG-IgA) as the primary test, followed by duodenal biopsy for confirmation, and treatment consists of a strict lifelong gluten-free diet under the supervision of a specialized nutritionist. 1
Diagnostic Testing Algorithm
Step 1: Initial Serological Testing
- Measure total IgA serum levels to rule out IgA deficiency 1
- Perform tTG-IgA testing as the primary serological test (sensitivity 97.7%, specificity 70.2% in children) 1
- If IgA deficient, use IgG-based tests (IgG-tTG or IgG-DGP) instead 1
- In children under 2 years, combine tTG-IgA with IgG and IgA deamidated gliadin peptides for improved sensitivity 1
Step 2: Confirmatory Testing
- Upper endoscopy with multiple duodenal biopsies is mandatory for diagnosis 1
- Collect at least 6 specimens: 1-2 from the bulb and at least 4 from the distal duodenum 1
- Look for characteristic histological findings:
- Increased intraepithelial lymphocytes (≥25/100 enterocytes)
- Crypt hyperplasia
- Villous atrophy 1
Step 3: Genetic Testing (in specific situations)
- Not recommended for routine diagnosis
- Useful in:
- Seronegative cases with suspected celiac disease
- Equivocal small-bowel histologic findings
- High-risk populations 1
- HLA-DQ2/DQ8 negative results have >99% negative predictive value 1
Treatment Protocol
Primary Treatment
- Strict lifelong gluten-free diet is the only currently effective treatment 1, 2
- Implementation should be supervised by a registered dietitian experienced in celiac disease 1
Nutritional Management
- Perform nutritional assessment and supplement any deficiencies:
- Iron
- Folate
- Vitamin B12 1
- Assess bone mineral density to evaluate for osteoporosis 1
Monitoring and Follow-up
Serological Monitoring
- Monitor with anti-tTG antibodies at:
- 6 months after diagnosis
- 12 months after diagnosis
- Annually thereafter 1
- Note: Negative serology does not guarantee intestinal healing (sensitivity <50% for detecting persistent villous atrophy) 1, 3
Clinical Assessment
- Annual evaluation for:
- Symptom resolution
- Nutritional status
- Weight management 1
Monitoring for Complications
- Watch for persistent symptoms despite adherence to a gluten-free diet
- Consider refractory celiac disease or complications like enteropathy-associated T-cell lymphoma 1
- Video capsule endoscopy recommended for patients with refractory celiac disease and unexplained symptoms 1
Special Considerations
High-Risk Populations
- First-degree relatives (7.5% risk)
- Patients with:
- Type 1 diabetes
- Autoimmune thyroid disease
- Down syndrome
- Turner syndrome
- Unexplained iron deficiency anemia 1
Seronegative Celiac Disease
- Characterized by villous atrophy with negative serology
- Requires exclusion of other causes of atrophy
- Evaluate response to a gluten-free diet 1
- For seronegative patients with villous atrophy and genetic risk factors, endoscopic evaluation after 1-3 years on a gluten-free diet is recommended 1
Common Pitfalls to Avoid
Relying solely on serological tests for diagnosis: While tTG-IgA is highly sensitive, duodenal biopsy remains the gold standard for diagnosis 1, 2
Missing IgA deficiency: Always check total IgA levels before interpreting tTG-IgA results 1
Inadequate biopsy sampling: Collect at least 6 specimens from different parts of the duodenum to avoid missing patchy lesions 1
Overlooking seronegative celiac disease: Some patients (15.5%) may have negative tTG-IgA but positive DGP antibodies and biopsy-confirmed celiac disease 4, 5
Assuming mucosal healing based on negative serology: A normal tTG level does not predict recovery of villous atrophy in patients on a gluten-free diet 3
Incomplete monitoring: Regular follow-up is essential to ensure dietary adherence and detect complications 1