Diagnostic Significance of Combining Anti-Gliadin IgA and Anti-Tissue Transglutaminase IgA in Suspected Celiac Disease: A Cross-Sectional Study

Abstract

Objective: To explore the correlation between anti-gliadin IgA and anti-tTG IgA in 384 subjects suspected of celiac disease.

Study Design: Cross-sectional descriptive study.
Place and Duration of Study: This study was conducted at the Laboratories of the Biology Department, College of Education, University of Al-Qadisiyah, Iraq; February to December 2025.

Methods: ELISA testing of sera using commercial kits, with results interpreted against manufacturer-defined cut-off values.

Results: Positivity for anti-gliadin IgA occurred in 13.3% of cases, whereas 15.1% were positive for anti-tTG IgA. Co-positivity for both antibodies was seen in 8.1%, whereas 5.2% and 7.0% were positive only for anti-gliadin IgA
and anti-tTG IgA, respectively. Paired analysis disclosed a highly significant correlation (χ²=91.64, p<0.001, φ=0.49). More females were positive for both antibodies, consistent with established sex differences in autoimmune
conditions.

Conclusion: Results underscore the combined utility of anti-gliadin IgA and anti-tTG IgA, particularly in discordant cases, supporting multiple-test strategies for improved celiac detection with reduced false negatives.