title: Positive tissue transglutaminase antibodies with negative endomysial antibodies: low rate of celiac disease.
abstract: BACKGROUND
  Screening for celiac disease is based on the sequential evaluation of serologic tests and intestinal biopsy; an optimal screening protocol is still under investigation. The screening policy of one of the main healthcare providers in Israel (Maccabi) consists of measuring total immunoglobulin A and tissue transglutaminase IgA antibodies and confirming positive results by endomysial antibodies. For IgA-deficient patients antigliadin IgG is measured.
  
  
  OBJECTIVE
  To evaluate the use of tTGA as a first-level screening test in patients suspected of having celiac disease
  
  
  METHODS
  The results of tTGA and EMA tests over a 3 month period were obtained from the laboratory computer. Letters were sent to the referring physicians of patients with positive tests, requesting clinical information and small intestinal biopsy results. tTGA was performed using an anti-guinea pig tTG-IgA enzyme-linked immunosorbent assay kit.
  
  
  RESULTS
  Overall, 2,505 tTGA tests were performed: 216 (8.6%) were tTGA-positive of which 162 (75%) were EMA-negative (group 1) and 54 (25%) EMA-positive (group 2.) Clinical information was obtained for 91 patients in group 1 and 32 in group 2. Small intestinal biopsy was performed in 33 (36%) and 27 patients (84%) in groups 1 and 2, respectively. Celiac disease was diagnosed in 4 biopsies (12%) in group 1 and 23 (85%) in group 2 (P < 0.0001). The positive predictive value was 45% for tTGA and 85% for EMA.
  
  
  CONCLUSIONS
  Symptomatic patients with positive tTGA and negative EMA have a low rate of celiac disease compared to those who are tTGA-positive and EMA-positive. Confirmation with EMA is advised when tTGA is performed as a first-level screening for suspected celiac disease.
authors.affiliation: Division of Pediatric Gastroenterology and Nutrition, Edmond and Lily Safra Children's Hospital, Israel. weissb@sheba.health.gov.il
authors.forename: Batia
authors.initials: B
authors.lastname: Weiss
authors.forename: Yoram
authors.initials: Y
authors.lastname: Bujanover
authors.forename: Benjamin
authors.initials: B
authors.lastname: Avidan
authors.forename: Akiva
authors.initials: A
authors.lastname: Fradkin
authors.forename: Ilana
authors.initials: I
authors.lastname: Weintraub
authors.forename: Bracha
authors.initials: B
authors.lastname: Shainberg
mesh_terms: D000293:Adolescent; D000328:Adult; D001323:Autoantibodies / Q000032:analysis* / Q000097:blood*; D015982:Bias; D015415:Biomarkers / Q000032:analysis / Q000097:blood; D001706:Biopsy / Q000379:methods* / Q000592:standards; D002446:Celiac Disease / Q000175:diagnosis* / Q000453:epidemiology / Q000276:immunology / Q000378:metabolism; D004386:Duodenum / Q000201:enzymology / Q000276:immunology / Q000473:pathology; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods / Q000592:standards; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D005903:Gliadin / Q000276:immunology; D006801:Humans; D007070:Immunoglobulin A / Q000032:analysis* / Q000097:blood*; D007074:Immunoglobulin G / Q000032:analysis / Q000097:blood; D007557:Israel / Q000453:epidemiology; D008297:Male; D008403:Mass Screening / Q000379:methods* / Q000592:standards; D015995:Prevalence; D012680:Sensitivity and Specificity; D011503:Transglutaminases / Q000276:immunology*
chemical_list: D001323:Autoantibodies; D015415:Biomarkers; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D005903:Gliadin; D011503:Transglutaminases