From the Guidelines
The recommended approach for a celiac disease screen is to start with serological testing, specifically tissue transglutaminase antibody (tTG-IgA) along with total serum IgA to rule out IgA deficiency, as suggested by the most recent guidelines 1.
Key Considerations
- This initial blood test should be performed while the patient is on a gluten-containing diet, as eliminating gluten before testing can lead to false negative results.
- If the tTG-IgA is positive or if there is IgA deficiency, additional testing with deamidated gliadin peptide antibodies (DGP-IgG) may be performed.
- Patients with positive serological tests should then undergo an upper endoscopy with multiple duodenal biopsies for histological confirmation before starting a gluten-free diet.
Importance of Screening
- Screening is particularly recommended for first-degree relatives of celiac patients, those with autoimmune conditions like type 1 diabetes or thyroid disease, and patients with unexplained symptoms such as chronic diarrhea, weight loss, iron deficiency anemia, or elevated liver enzymes.
- Genetic testing for HLA-DQ2 and HLA-DQ8 can be useful in certain cases to rule out celiac disease, as their absence makes the diagnosis highly unlikely, as noted in earlier guidelines 1.
Recent Guidelines
- The most recent guidelines from 2024 1 emphasize the importance of monitoring established coeliac disease in adult patients, highlighting the need for a strict, life-long gluten-free diet and regular follow-up.
- These guidelines support clinicians in improving celiac disease treatment and follow-up, and highlight novel issues that should be considered in future studies.
From the Research
Celiac Disease Screening Approach
The recommended approach for a celiac disease screen involves the use of serologic tests, including:
- Tissue transglutaminase antibodies (tTG) 2, 3, 4, 5
- Endomysial antibodies (EMA) 2, 3, 4, 5
- Antigliadin antibodies (AGA) 4
Sensitivity and Specificity of Serologic Tests
The sensitivity and specificity of these tests vary, with:
- tTG IgA assay having a sensitivity of 0.50 (95% CI, 0.41-0.60) and specificity of 0.83 (95% CI, 0.79-0.87) 2
- EMA IgA assay having a sensitivity of 0.45 (95% CI, 0.34-0.57) and specificity of 0.91 (95% CI, 0.87-0.94) 2
- IgA and IgG TGA offering 100% sensitivity in CD patients for whom no dietary intervention had been commenced, with a specificity of 61% 4
Diagnostic Criteria
The diagnosis of celiac disease is based on:
- Positive serologic tests 2, 3, 4, 5
- Villous atrophy on small bowel biopsy 2, 3, 6
- Clinical symptoms and response to a gluten-free diet 3, 6
Monitoring and Follow-up
Monitoring and follow-up of patients with celiac disease involve:
- Regular serologic tests to assess dietary compliance 3, 4
- Small bowel biopsy to assess mucosal recovery 2, 3, 6
- Clinical evaluation to assess symptoms and response to treatment 3, 6
Special Considerations
Special considerations in celiac disease screening include: