title: Diagnostic accuracy of serological assays in pediatric inflammatory bowel disease.
abstract: OBJECTIVE
  Accurate serological assays are desirable for the diagnosis of inflammatory bowel disease (IBD) types in the pediatric age group. The aim of this study was to test the diagnostic accuracy of modified assays for perinuclear (p) antineutrophil cytoplasmic antibodies (ANCAs) and anti-Saccharomyces cerevisiae antibodies (ASCAs) in patients with pediatric ulcerative colitis (UC) and Crohn's disease (CD) and in those without IBD.
  
  
  METHODS
  With observers blinded to patients' diagnoses, serum specimens were analyzed for immunoglobulin (Ig) A and IgG ASCAs and ANCAs by enzyme-linked immunosorbent assay. The perinuclear location of ANCAs visualized by indirect immunofluorescence was confirmed by its disappearance after administration of deoxyribonuclease.
  
  
  RESULTS
  IgA and IgG ASCA titers were significantly greater and highly specific for CD (95% for either, 100% if both positive). pANCA was 92% specific for UC and absent in all non-IBD controls. The majority of patients with CD positive for pANCA had a UC-like presentation. Disease location, duration, activity, complications, and treatment with immunosuppressive drugs did not have an impact on the ASCA or pANCA assay results. After resection, UC patients remained pANCA positive, in contrast to patients with CD, in whom ASCA titers decreased toward normal values postoperatively.
  
  
  CONCLUSIONS
  ASCA and pANCA assays are highly disease specific for CD and UC, respectively. These serological tests can assist clinicians in diagnosing and categorizing patients with IBD and may be useful in making therapeutic decisions.
authors.affiliation: Division of Gastroenterology-Nutrition, Department of Pediatrics, Ste-Justine Hospital, University of Montreal, Montreal, Quebec, Canada.
authors.forename: F M
authors.initials: FM
authors.lastname: Ruemmele
authors.forename: S R
authors.initials: SR
authors.lastname: Targan
authors.forename: G
authors.initials: G
authors.lastname: Levy
authors.forename: M
authors.initials: M
authors.lastname: Dubinsky
authors.forename: J
authors.initials: J
authors.lastname: Braun
authors.forename: E G
authors.initials: EG
authors.lastname: Seidman
mesh_terms: D000293:Adolescent; D000328:Adult; D019268:Antibodies, Antineutrophil Cytoplasmic / Q000032:analysis; D000908:Antibodies, Fungal / Q000032:analysis; D002648:Child; D003093:Colitis, Ulcerative / Q000175:diagnosis* / Q000276:immunology / Q000601:surgery; D003424:Crohn Disease / Q000175:diagnosis* / Q000276:immunology / Q000601:surgery; D006801:Humans; D007070:Immunoglobulin A / Q000032:analysis; D007074:Immunoglobulin G / Q000032:analysis; D011184:Postoperative Period; D012441:Saccharomyces cerevisiae / Q000276:immunology; D012698:Serologic Tests / Q000592:standards*
chemical_list: D019268:Antibodies, Antineutrophil Cytoplasmic; D000908:Antibodies, Fungal; D007070:Immunoglobulin A; D007074:Immunoglobulin G