High Tissue-transglutaminase Antibody Level Predicts Small Intestinal Villous Atrophy in Adult Patients at High Risk of Celiac Disease

Background: Duodenal biopsy may be unnecessary to confirm celiac disease in patients with high tissue-transglutaminase antibody level.

Aims: To define a cut-off value of tissue-transglutaminase antibody with high positive likelihood ratio for duodenal atrophy in patients with suspected celiac disease.

Methods: We retrospectively identified 945 patients with suspected celiac disease and classified according to the method used for tissue-transglutaminase antibody assay: Group A (n=393, Eu-tTG® Eurospital), Group B (n=263; Eu-tTG® Eurospital) and Group C (n=289; Celikey® Phadia). Duodenal histology was graded according to Marsh. Sensitivity, specificity, and positive likelihood ratio were used to evaluate cut-off points of tissue-transglutaminase antibody as predictor of villous atrophy.

Results: 100% specificity and ∞ positive likelihood ratio for duodenal atrophy was observed at a cut-off value of tissue-transglutaminase antibody 5 times higher than the upper limit of normal. CD diagnosis was confirmed by concordance with antiendomysial antibodies, and by reduction of t-TG titre in all patients and improvement of duodenal histology in 80% during gluten-free diet.

Conclusions: Tissue-transglutaminase antibody level 5-folds the upper limit of normal is 100% specific for duodenal atrophy and using this cut-off biopsy could by avoided in 1/3 of patients. Diagnostic criteria of celiac disease in adults need revision.