BACKGROUND: Anti-tissue transglutaminase (tTG) antibody is being used increasingly as a diagnostic tool in the serological investigation of coeliac disease. However, positive predictive values of immunoglobulin A (IgA) anti-tTG for coeliac disease in prospective studies have been disappointing and false-positive results are reported. OBJECTIVE: To assess the clinical utility of cascade testing for anti-tTG and anti-endomysium antibody (AEA). PATIENTS: Two unselected retrospective cohorts from routine diagnostic investigation for possible gluten sensitive enteropathy: group 1 comprised 57 cases seropositive for anti-tTG and group 2 comprised 52 cases seronegative for anti-tTG. In both groups, all cases had also undergone small-intestinal biopsy. METHODS: Patients were assessed for the presence of IgA anti-tTG by enzyme-linked immunosorbent assay and for IgA AEA by immunofluorescence. RESULTS: The positive predictive value of IgA anti-tTG for biopsy-confirmed coeliac disease was 54%. The positive predictive value of dual positivity for anti-tTG and AEA was 97%. The negative predictive value of IgA anti-tTG was 100%. CONCLUSIONS: The data presented here support the use of IgA anti-tTG as an initial screen for coeliac disease. Coeliac disease is unlikely when IgA anti-tTG is absent. However, many false-positive results are seen, and clinical utility and diagnostic efficiency are improved markedly if positive results are confirmed with the more accurate, but labour-intensive, AEA assay.
BACKGROUND: Anti-tissue transglutaminase (tTG) antibody is being used increasingly as a diagnostic tool in the serological investigation of coeliac disease. However, positive predictive values of immunoglobulin A (IgA) anti-tTG for coeliac disease in prospective studies have been disappointing and false-positive results are reported. OBJECTIVE: To assess the clinical utility of cascade testing for anti-tTG and anti-endomysium antibody (AEA). PATIENTS: Two unselected retrospective cohorts from routine diagnostic investigation for possible gluten sensitive enteropathy: group 1 comprised 57 cases seropositive for anti-tTG and group 2 comprised 52 cases seronegative for anti-tTG. In both groups, all cases had also undergone small-intestinal biopsy. METHODS:Patients were assessed for the presence of IgA anti-tTG by enzyme-linked immunosorbent assay and for IgAAEA by immunofluorescence. RESULTS: The positive predictive value of IgA anti-tTG for biopsy-confirmed coeliac disease was 54%. The positive predictive value of dual positivity for anti-tTG and AEA was 97%. The negative predictive value of IgA anti-tTG was 100%. CONCLUSIONS: The data presented here support the use of IgA anti-tTG as an initial screen for coeliac disease. Coeliac disease is unlikely when IgA anti-tTG is absent. However, many false-positive results are seen, and clinical utility and diagnostic efficiency are improved markedly if positive results are confirmed with the more accurate, but labour-intensive, AEA assay.
Authors: Jonathan D Godfrey; Tricia L Brantner; Waleed Brinjikji; Kevin N Christensen; Deanna L Brogan; Carol T Van Dyke; Brian D Lahr; Joseph J Larson; Alberto Rubio-Tapia; L Joseph Melton; Alan R Zinsmeister; Robert A Kyle; Joseph A Murray Journal: Gastroenterology Date: 2010-06-01 Impact factor: 22.682
Authors: Andrew D Hopper; Simon S Cross; David P Hurlstone; Mark E McAlindon; Alan J Lobo; Marios Hadjivassiliou; Marion E Sloan; Simon Dixon; David S Sanders Journal: BMJ Date: 2007-03-23
Authors: M Ankelo; V Kleimola; S Simell; O Simell; M Knip; E Jokisalo; M Tarkia; A Westerlund; Q He; M Viander; J Ilonen; A E Hinkkanen Journal: Clin Exp Immunol Date: 2007-09-04 Impact factor: 4.330
Authors: Lucas Malta Almeida; Luiz Claudio Castro; Rosa Harumi Uenishi; Fernanda Coutinho de Almeida; Patricia Maria Fritsch; Lenora Gandolfi; Riccardo Pratesi; Yanna Karla de Medeiros Nóbrega Journal: World J Gastroenterol Date: 2013-03-28 Impact factor: 5.742