Background: With high diagnostic accuracy of serological test like Ig A tissue transglutaminase (tTG) in celiac disease (CD), the necessity for small intestinal biopsy has been questioned. 

Aim: To ascertain the correlation between serum levels of IgA anti- tTG with histological severity and to predict the cut-off tTG levels, which would predict the presence of Marsh =2 changes in histology diagnostic of CD. 

Methods: A prospective study was done in the pediatric age group of 2-18 years with suspected coeliac disease. All were tested for a-tTG, followed by endoscopic biopsy in patients with positive serology. Histology was assessed according to Modified Marsh grading. Receiver operating curve (ROC), sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV), were used to find the cutoff anti-tTG levels confirming CD.

Results: 162 symptomatic subjects were included in the study of which 126 had histology confirmatory of CD.Marsh grade 2 changes were seen in 2.3%, 3a in 27%, 3b in 24.6% and 3c in 46 % respectively. Higher grades of Marsh injury were associated with progressively increasing anti tTG levels, which was statistically significant (p=0.015). ROC curve showed cutoff of 76 U/ml with sensitivity, specificity, PPV and NPV of 84.1%, 97.2%, 99.07% and 63.64 % respectively. 

Conclusion: There is positive correlation between serum levels of anti tissue trans glutaminase and stage of mucosal injury, so the diagnosis of CD can be reached without endoscopic biopsy. This will avoid an invasive, traumatic and costly procedure in children and lead to more rapid diagnosis.