title: Are positive serum-IgA-tissue-transglutaminase antibodies enough to diagnose coeliac disease without a small bowel biopsy? Post-test probability of coeliac disease.
abstract: BACKGROUND
  It has been suggested that high titres of tTG are associated with elevated positive predictive values (PPV) for celiac disease. However, the PPV of a strongly positive tTG will depend on the celiac disease prevalence in the different risk groups of the disease
  
  
  OBJECTIVE
  To assess the PPV of a strongly positive tTG for celiac disease. In addition, to calculate the post-test probability for celiac disease of a strongly positive tTG in a setting of routine clinical practice.
  
  
  METHODS
  145 consecutive celiac disease patients with positive tTG, and with a small bowel biopsy were included. The PPV for different cut-off points of tTG levels for the diagnosis of celiac disease was assessed. In addition, the cut-offs associated with higher PPV were used to calculate the positive likelihood ratio. A simulation in a setting of routine clinical practice was performed to calculate the post-test probability of celiac disease.
  
  
  RESULTS
  No cut-off level was associated with a PPV of 100%. A cut-off of 80 U/mL (11.4×upper normal limit) was associated with the higher PPV value of 98.6%. In the most frequent clinical situations, which in general have a pre-test probability <10%, the post-test probability after having a strongly positive tTG was 90% or less.
  
  
  CONCLUSIONS
  A strongly positive tTG should not be enough to diagnose celiac disease in the most frequent clinical situations, small bowel biopsy remaining as the gold standard in these cases.
authors.affiliation: Department of Gastroenterology, Hospital Universitari Mutua Terrassa, University of Barcelona, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas-CIBERehd, Terrassa, Barcelona, Spain. ffbanares@mutuaterrassa.es
authors.forename: Fernando
authors.initials: F
authors.lastname: Fernández-Bañares
authors.forename: Montserrat
authors.initials: M
authors.lastname: Alsina
authors.forename: Inés
authors.initials: I
authors.lastname: Modolell
authors.forename: Xavier
authors.initials: X
authors.lastname: Andújar
authors.forename: Marta
authors.initials: M
authors.lastname: Piqueras
authors.forename: Roger
authors.initials: R
authors.lastname: García-Puig
authors.forename: Benjamín
authors.initials: B
authors.lastname: Martín
authors.forename: Mercé
authors.initials: M
authors.lastname: Rosinach
authors.forename: Antonio
authors.initials: A
authors.lastname: Salas
authors.forename: Josep Maria
authors.initials: JM
authors.lastname: Viver
authors.forename: Maria
authors.initials: M
authors.lastname: Esteve
mesh_terms: D000293:Adolescent; D000328:Adult; D001706:Biopsy; D002446:Celiac Disease / Q000097:blood / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology; D002648:Child; D005260:Female; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood / Q000276:immunology*; D007421:Intestine, Small / Q000473:pathology*; D016013:Likelihood Functions; D008297:Male; D012680:Sensitivity and Specificity; D011503:Transglutaminases / Q000378:metabolism*; D055815:Young Adult
chemical_list: D007070:Immunoglobulin A; D011503:Transglutaminases