Original Article This work is licensed under the Creative Commons Attribution 4.0 License. Published by Pacifc Group of e-Journals (PaGe) Correlation of Serum Tissue Transglutaminase Antibody Levels and Marsh Grading of Duodenal Biopsy in Patients of Celiac Disease Introduction Malabsorption is a disease condition characterized by defective absorption of fats, proteins, carbohydrates, fat and water-soluble vitamins, electrolytes and minerals. Celiac disease is considered as one of the most common causes of malabsorption. [1] In 2013 Oslo defned Celiac diseases as a chronic small intestinal immune-mediated enteropathy precipitated in genetically predisposed individuals by exposure to dietary gluten .[2] Celiac disease (CD), also called as gluten-sensitive enteropathy, endemic sprue and non-tropical sprue. It is an autoimmune disorder triggered by the ingestion of wheat gluten and related proteins of barley and rye in genetically susceptible adults and children. [3] Well-identifed haplotypes in the human leukocyte antigen (HLA) class II region like HLA-DQ8 and HLA-DQ2 confer genetic susceptibility. [4] The risk of having Celiac disease is high in frst-degree relatives (10%) and in second-degree relatives (5%), as well in people with autoimmune diseases, diabetes, Down’s syndrome and a number of other associated diseases. [5] A defnite diagnosis of Celiac disease is based on histological changes, including intraepithelial lymphocytosis, crypt hyperplasia, and varying degrees of villous atrophy, graded according to a classifcation system proposed by Marsh in 1992 and now widely used as modifed Marsh grading depicted in table 1. [6-9] Duodenal biopsy remains the gold standard for diagnosis of CD, even though there are very specifc serologic tests like anti-gluten and anti-tissue transglutaminase (anti- tTG) antibodies. Correlation of clinical, serologic, and histological features is essential for the defnitive diagnosis of this condition. [10] Benjith Paul*, Prateek Kinra, Bhaskar Nandi and AS Prasad Department of Pathology and Internal Medicine, Command Hospital Air Force, Bangalore, India ABSTRACT Background: Celiac disease (CD) is a chronic small intestinal immune-mediated enteropathy precipitated in genetically predisposed individuals by ingestion of wheat gluten and related proteins of barley and rye. It is an under-diagnosed gluten-sensitive enteropathy, usually presenting with atypical/extra-intestinal features. Duodenal biopsy is considered as the gold standard in the diagnosis of CD. Serum anti tissue transglutaminase (anti-tTG) antibodies isauto antibodies directed against tissue transglutaminase (tTG) enzyme.Aims and objective: The aim of the study is to fnd out the prevalence of CD among clinically suspected cases of malabsorption, to assess the correlation of anti-tTG levels with modifed Marsh grading of duodenal biopsy, to fnd out sensitivity, specifcity and predictive values of anti-tTG test and to calculate the cut off values of anti-tTG diagnostic of high grade CD. Methodology: The present study included 118 clinically suspected patients of malabsorption in which both duodenal biopsy and anti-tTG test was done. The mucosal damage graded according to the modifed Marsh grading and anti-tTG tests were done in serum using ELISA kit. Results: The prevalence of CD among clinically suspected cases of malabsorption was 12.7%. The incidence was highest in middle aged male patients. The most common clinical symptom was chronic diarrhea and commonest presenting sign was anemia. Anti-tTG levels were found to be proportionately increasing with the severity of CD and showed a positive correlation(r=0.433). Patients with anemia and chronic diarrhea showed statistically signifcant (p value=0.0242 and 0.0089 respectively) mean anti-tTG levels in Celiac patients in relation to non-Celiac patients. Although the mean levels of anti-tTG was 6.3 times higher than baseline in grade 3 disease, the ROC analysis showed that anti-tTG in isolation had no signifcance in exactly grading the disease (AUC=0.30). Conclusion: Positive correlation was found between anti-tTG levels and modifed Marsh grading. Anti-tTG showed proportionate increase with severity of duodenal damage.Anti-tTG test showed low sensitivity (42.86%) and high specifcity (84.34%). Hence it is not a reliable tool in isolation to screen CD but should be used in combination with duodenal biopsy. It can be used to assess the severity of CD and for follow up. Keywords: Malabsorption, Celiac Disease (CD), Duodenal Biopsy, Modified Marsh Grading, Serum Anti Tissue Transglutaminase (anti-tTG) Test. DOI: 10.21276/APALM.2314