The Evolution in the Diagnosis and Monitoring of Celiac Disease

Celiac disease (CD) is being increasingly diagnosed with an overall prevalence of approximately 1%. This expert review provides an update on the diagnosis and follow-up of celiac disease. 

Key points:

• Tissue transglutaminase-IgA (TG2-IgA) and IgA testing play a crucial role in the detection and diagnosis of CD.
  
• TG2-IgA level > x 10 ULN is a reliable and accurate test for diagnosing CD. This, combined with a positive endomysial antibody (EMA) in a separate blood sample, makes the positive predictive value for CD virtually 100%. 
  
• In patients with significant IgA deficiency, IgG deaminated gliadin antibody tests and TG2-IgG testing are recommended.
  
• In patients found to have CD first by intestinal biopsies, celiac-specific serology should be undertaken as a confirmatory test prior to initiation of a gluten-free diet (GFD).
  
• When clinical suspicion of CD is high in the setting of negative biopsies, TG2-IgA should still be performed and, if positive, repeat biopsies be considered.
  
• Reduction or avoidance of gluten prior to diagnostic testing may reduce the sensitivity of serology and histology; therefore, a normal diet should be resumed with 3 slices of wheat bread for 1-3 months prior to checking Tg2-IgA.
  
• The role for serology in follow up is less well-defined. While a positive serology in a treated patient usually indicates continued intestinal damage/gluten exposure, a negative serology does not guarantee intestinal healing. Follow-up serology is recommended at 6, 12 months after diagnosis, and yearly thereafter.
  
• Patients with refractory or recurrent symptoms should undergo endoscopic biopsies to determine healing even in the presence of negative TG2-IgA.