Diagnostic accuracy of IgA anti-tissue transglutaminase for the diagnosis of coeliac disease.

INTRODUCTION

A no-biopsy approach has been suggested for diagnosing coeliac disease (CD) in adult patients. This approach is already well established in diagnosing children with CD. This study aimed to evaluate the accuracy of IgA anti-tissue transglutaminase (IgA anti-tTG) in predicting duodenal mucosal lesions diagnostic of CD in adult patients.

METHODS

We included all patients aged ≥ 18 years referred for CD diagnostics at our department in the period from 1 January 2019 to 31 December 2023 with raised IgA anti-tTG levels and in whom duodenal biopsies had been evaluated for CD-specific lesions. Data regarding IgA anti-tTG levels and duodenal histology evaluated by the modified Marsh classification were retrieved from the patient records.

RESULTS

A total of 235 adult patients had positive IgA anti-tTG levels and an available duodenal histology. High IgA anti-tTG levels (> 10 × upper limit of normal (ULN)) were associated with more severe enteropathy. The PPV of IgA anti-tTG for identifying Marsh ≥ 2 or 3 lesions increased when the serological cut-off was raised. The positive predictive value of IgA anti-tTG > 10 × ULN was 99.2% (95% CI: 95.8-100%) and 97.7% (95% CI: 93.4-99.5%) for predicting Marsh ≥ 2 and 3 lesions, respectively.

CONCLUSIONS

This study confirms that high titers of IgA anti-tTG may accurately identify adults with diagnostic duodenal mucosal lesions associated with CD. Our data support the use of a no-biopsy approach for diagnosing CD in adults with high IgA anti-tTG titers.

FUNDING: None.

TRIAL REGISTRATION: Not relevant.