Can Duodenal Biopsy Be Omitted in Patient With Positive Serum tTGA Antibody in The Diagnosis of Celiac Disease?

Abstract

Background: Celiac disease (CD) is caused by a reaction to the dietary gluten in genetically predisposed individuals. Measuring of serum IgA antibodies to human tissue transglutaminase (tTGA) can be used alone for the diagnosis of celiac disease. However, it is recommended that individuals with positive tTGA antibodies should have a duodenal biopsy to confirm the diagnosis of CD. Objectives: This study aims to clarify the extent to which the anti tTGA serological assay can replace the need for performing duodenal biopsy in the diagnosis of CD. Patients and Methods: This study was conducted in the Basrah University Teaching Hospital laboratory, Jasim Aldiab laboratory, and Al-Moosawi private hospital in the period of 1st January 2019 to 1st October 2021. The cases included in this study are 190 individuals subjected to tTGA serological test and duodenal biopsy. Marsh I and Marsh II categories were not considered diagnostic of CD, while Marsh III category was considered diagnostic of CD. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the tTGA test were calculated. Results: The sensitivity of the tTGA was 57.1%, the specificity was 92%, the PPV was 95.2%, and the NPV was 43.4%. Conclusions: The study concludes that the duodenal biopsy can be omitted in patients with negative serum tTGA antibody because of high specificity but cannot be used as a sole tool for the diagnosis of CD because of low sensitivity. Thus, depending on the serological test could lead to missed diagnosis of some CD cases.