title: Tissue transglutaminase enzyme-linked immunosorbent assay as a screening test for celiac disease in pediatric patients.
abstract: OBJECTIVE
  An immunoglobulin A (IgA) anti-tissue transglutaminase antibody assay (anti-tTG) was compared with the conventional IgA anti-endomysium antibody assay (EMA) to assess its reliability as a screening test for celiac disease (CD) in a pediatric population.
  
  
  METHODS
  Seventy-five IgA-sufficient and 2 IgA-deficient children who were scheduled for small intestinal biopsy for the evaluation of history or symptoms suggesting a diagnosis of CD were prospectively evaluated and enrolled in this study (gastrointestinal [GI] patients). In addition, 16 children with type I diabetes mellitus (DM) who had a positive EMA and a small bowel biopsy were included as a separate cohort. IgA anti-tTG was measured by enzyme-linked immunosorbent assay (ELISA), and IgA-EMA titers were determined by indirect immunofluorescence on cryopreserved sections of monkey esophagus.
  
  
  RESULTS
  Nine of the 75 IgA-sufficient GI patients had a small bowel biopsy consistent with the diagnosis of CD. Eight of 9 IgA-sufficient patients with a positive small bowel biopsy had positive anti-tTG and EMA tests. Four IgA-sufficient patients had a false-positive anti-tTG ELISA and 2 had a false-positive IgA-EMA assay. In the IgA-sufficient patients, the sensitivity was 89% and the negative predictive value was 98% for either assay. The specificities of the IgA anti-tTG and the IgA-EMA tests were 94% and 97%, respectively (not significant). The positive predictive value of the IgA anti-tTG was 67%, compared with 80% for the IgA-EMA (not significant). In the 2 IgA-deficient children, one of whom had biopsy-proved CD, both tests were negative. In the 16 DM children 12 true- and 4 false-positive IgA anti-tTG and IgA-EMA results were identified. Three of 12 complained of GI symptoms. In follow-up, thus far, none of the DM patients with a false-positive anti-tTG have developed CD.
  
  
  CONCLUSIONS
  The IgA anti-tTG antibody assay is equivalent to the IgA-EMA assay as a screening test for CD in IgA-sufficient pediatric patients. Intestinal biopsy remains the gold standard for the diagnosis of CD.
authors.affiliation: Department of Medicine, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada.
authors.forename: A W
authors.initials: AW
authors.lastname: Chan
authors.forename: J D
authors.initials: JD
authors.lastname: Butzner
authors.forename: R
authors.initials: R
authors.lastname: McKenna
authors.forename: M J
authors.initials: MJ
authors.lastname: Fritzler
mesh_terms: D015746:Abdominal Pain / Q000209:etiology; D000293:Adolescent; D001323:Autoantibodies / Q000032:analysis; D001706:Biopsy; D002446:Celiac Disease / Q000150:complications / Q000175:diagnosis*; D002648:Child; D002675:Child, Preschool; D003922:Diabetes Mellitus, Type 1 / Q000150:complications; D004797:Enzyme-Linked Immunosorbent Assay; D005188:False Negative Reactions; D005189:False Positive Reactions; D006801:Humans; D007070:Immunoglobulin A / Q000032:analysis; D007223:Infant; D007421:Intestine, Small / Q000473:pathology; D008403:Mass Screening / Q000295:instrumentation* / Q000379:methods; D011237:Predictive Value of Tests; D011446:Prospective Studies; D015203:Reproducibility of Results; D012189:Retrospective Studies; D011503:Transglutaminases / Q000276:immunology
chemical_list: D001323:Autoantibodies; D007070:Immunoglobulin A; D011503:Transglutaminases