ONLY HIGH TITRE ANTI-TISSUE TRANSGLUTAMINASE ANTIBODIES CONSISTENTLY PREDICT CELIAC DISEASEBarker, Collin1; Jevon, Gareth2; Mock, Thomas3Journal of Pediatric Gastroenterology and Nutrition: October 2006 - Volume 43 - Issue 4 - p E43 North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition Annual Meeting, October 19-22, 2006, Orlando, Florida: Abstracts: POSTER SESSION II, FRIDAY, OCTOBER 20, 2006, 12:15 p.m. - 2:15 p.m.: Intestine/Colon/IBD: 92 Author InformationAuthors 1Pediatric Gastroenterology, BC Children's Hospital, Vancouver, BC, Canada; 2Pathology, BC Children's Hospital, Vancouver, BC, Canada; 3Patholgy and Laboratory Medicine, BC Children's Hospital, Vancouver, BC, Canada. Celiac Disease has been found to be far more common than previously recognized due to the widespread availability of highly sensitive and specific screening tests such as the anti-tissue transglutaminase antibody (TTG). The TTG has been reported to have a greater than 90% specificity and sensitivity. These reports did not look at antibody titres as part of their protocols. This prospective cohort study was designed to assess whether or not a high titre TTG was predictive of celiac disease and how it compared to mid-range titres and the overall predictive value using the recommended screening level titre cut-offs (≥20 U for this commercial kit). Methods: From January 2005 to April 2006, 289 patients age 9 months to 17 years were recruited. 101 potential subjects and 188 controls. All TTG results were either reported from or confirmed at our hospital laboratory. Results: All 188 controls had negative TTG results and biopsy results not in keeping with celiac disease based on the modified Marsh criteria. Of the 101 potential subjects, 3 had low IgA levels (all 3 normal biopsies, not in tables below), 10 with high TTG's on outside labs were normal on repeat testing, and 88 had raised TTG's. See Tables below. Conclusion: Only high titre TTG results (>200 U using our commercial kit) were reliable in predicting positive biopsy results. The sensitivity at the screening test cut-off titres (>20 U) was 100% but the specificity was only 85% (198/234) which is lower than previously reported. Table © 2006 Lippincott Williams & Wilkins, Inc.