Correlation Between Cut-off Level of Tissue Transglutaminase Antibody and Marsh Classification

Duodenal biopsy is required for diagnosis of celiac disease in adults, although some studies have suggested adequate accuracy of serology alone.
We aimed to assess the correlation between anti-tissue transglutaminase (tTG) titer and pathological findings and to define the specific level of tTG for predicting celiac disease in adults without the need for biopsy sampling.
This descriptive study was done on 299 participants. The tTG titer and pathological findings of duodenal biopsy samples were used for this study. Analysis of Receiver operating characteristic (ROC) curve was used to find a cut-off point of anti-tTG antibody for mucosal atrophy.
Mean tTG titers was significantly higher in patients graded as Marsh III≥ 3 (p=0.023). ROC curve analysis showed 89.1% sensitivity for cut-off point≥76.5 IU/mL of anti-tTG. For Marsh≥ II, specificity was 28% and positive predictive value was 91%.
There is a linear correlation between increasing tTG level and Marsh I to III. Specificity of tTG titer more than 200 was 100% for Marsh >2.