Celiac Disease Diagnosis and Monitoring

Diagnostic Criteria

The American Gastroenterological Association recommends TTG-IgA as the primary screening test for celiac disease, with a sensitivity of 90-97% and specificity of 96-100% 1, 2, 3, 4
The American Academy of Family Physicians suggests that TTG-IgA is the gold standard screening test for celiac disease, with tissue transglutaminase-2 being the major autoantigen recognized in celiac disease 1, 2
The sensitivity of TTG-IgA ranges from 90.7% to 97% in adults and children, making it highly effective at detecting celiac disease 1, 5
The specificity of TTG-IgA ranges from 96% to 100%, meaning positive results are highly reliable 1

The American Gastroenterological Association recommends that all diagnostic serologic testing must be performed before initiating a gluten-free diet, as gluten withdrawal causes antibody levels to decline and produces false-negative results 3, 4
Total IgA levels must be documented because IgA deficiency occurs in 1-3% of celiac disease patients, which causes falsely negative TTG-IgA results 1, 2, 8

The American Gastroenterological Association suggests that TTG-IgA serves as the primary marker for monitoring adherence to gluten-free diet and assessing treatment response 9
Follow-up testing should be performed 6 months after starting gluten-free diet, 12 months after diagnosis, and annually thereafter 5, 9

The American Gastroenterological Association recommends a two-step approach for confirmatory testing, including endomysial antibody (EMA) testing and upper endoscopy with duodenal biopsy 1, 2, 3, 4
EMA testing has excellent specificity (99.6% in adults) and is used as a second-line confirmation 1, 2
Upper endoscopy with duodenal biopsy remains the gold standard for diagnosis confirmation 3, 4