A comparison of antibodies to tissue transglutaminase with conventional serological tests in the diagnosis of coeliac disease.

Background Tissue transglutaminase is now recognized as the autoantigen for antiendomysial antibodies. Antibodies to tissue transglutaminase have been proposed as a valuable test for coeliac disease. Objective To determine the value of antibodies to tissue transglutaminase in the diagnosis of coeliac disease in our outpatient population. Methods Patients who underwent serological tests for coeliac disease during the first 18 months of the tissue transglutaminase antibody assay were retrospectively identified from the regional serology laboratory database. Patients’ symptoms were noted, along with serological results and duodenal histology in those patients who underwent duodenal biopsy. Results In total, 586 patients were identified as having been serologically tested for coeliac disease, of whom 92 patients (33 men; mean age 51.7 years) had been followed up with duodenal biopsies. Of these 92 patients, 29 (31%; 14 men; mean age 52.5 years) had histological features of coeliac disease. The 63 patients with normal histology (19 men; mean age 51.8 years) acted as controls. Weight loss was more frequent in coeliac disease patients compared to controls (7 vs 5; P = 0.04) whereas the frequency of anaemia (P = 0.85) and diarrhoea (P = 0.74) did not differ significantly between the two groups. The sensitivity and specificity of tissue transglutaminase antibodies (86%; 84%) were compared to those for antiendomysial antibodies (90%; 98%) and antigliadin antibodies (76%; 79%). Conclusions The diagnostic value of tissue transglutaminase antibodies was intermediate between that of antiendomysial antibodies and antigliadin antibodies. However, duodenal biopsy remains the gold standard diagnostic test for coeliac disease.