Accuracy for deamidated gliadin IgG for the diagnosis of celiac disease

Abstract

INTRODUCTION: Celiac disease (CD) is a common autoimmune disorder. Serological diagnosis is based on anti-endomysial antibody (IgA EMA), IgA anti-transglutaminase (IgA anti-tTG) and IgG gliadin deaminase (IgG GdP) tests; none with 100% sensitivity and specificity, making intestinal biopsy the gold standard for diagnosis.

OBJECTIVES: to evaluate the diagnostic accuracy of anti DGP IgG compared to duodenal biopsy result and to calculate the optimal cut-off value for anti DGP IgG.

MATERIALS AND METHODS: An observational, retrospective study was performed. We included 251 patients over 18 years of age seen in the Gastroenterology Service of Clinica Universitaria Reina Fabiola for suspected CD in the period from March 2021 to December 2022 who were requested anti tTG IgA, anti-DGP IgG and upper gastrointestinal videoendoscopy. Sensitivity and specificity of anti-DGP IgG for the diagnosis of CD were analyzed. The optimal cut-off value of anti-DGP IgG was calculated using ROC curves.

RESULTS: The optimal cut-off value was determined to be 25 U/ml. The sensitivity and specificity value for this value were 84.6% (CI: 66.5%-93.9%) and 85.8% (CI: 80.6%-89.7%) respectively.

CONCLUSION: Raising the cut-off value from 10 to 25 U/ml would improve the diagnostic accuracy of anti-DGP IgG

Further studies could evaluate the impact of this change in the diagnostic algorithm and the role of serologic monitoring as a follow-up of the disease.