title: Serological markers to differentiate between ulcerative colitis and Crohn's disease.
abstract: OBJECTIVE
  To assess prospectively the value of three serological tests for differentiating between ulcerative colitis and Crohn's disease, used either alone or combined.
  
  
  METHODS
  Coded serum samples from 63 patients with ulcerative colitis and 67 patients with Crohn's disease were analysed. Detection assays for the presence of perinuclear antineutrophil cytoplasmic antibodies (pANCA), serum agglutinating antibodies to anaerobic coccoid rods, and specific IgG antibodies against a Kd-45/48 immunological crossreactive mycobacterial antigen complex (ImCrAC) were studied. Sensitivity, specificity, pre- and post-test probabilities, likelihood ratios, and predictive values of each of these serological tests were determined.
  
  
  RESULTS
  The sensitivity and specificity of the pANCA test for the diagnosis of ulcerative colitis were 61 and 79%, respectively. The serum agglutination test for anaerobic coccoid rods had a sensitivity of 42% and a specificity of 89% for a diagnosis of Crohn's disease. The sensitivity of specific IgG antibodies against Kd-45/48 ImCrAC in diagnosing Crohn's disease was 70% and specificity 60%. Although 100% specificity was achieved by combining all three tests in a small group of patients with Crohn's disease (n = 20), combining two or more tests had no additive clinical value. No correlation was found between the presence of any one of these antibodies and disease activity, duration, or localisation of disease. Surgery or medical treatment did not influence the presence of antibodies or the antibody titre.
  
  
  CONCLUSIONS
  The value of these tests in the differential diagnosis between ulcerative colitis and Crohn's disease is limited, but the high predictive values and specificities of different tests for both diseases suggest that these tests may be of help in studying disease heterogeneity and in defining different subgroups of patients with different pathogenesis.
authors.affiliation: Department of Gastroenterology, Free University Hospital, Amsterdam, The Netherlands.
authors.forename: M
authors.initials: M
authors.lastname: Oudkerk Pool
authors.forename: G
authors.initials: G
authors.lastname: Bouma
authors.forename: S G
authors.initials: SG
authors.lastname: Meuwissen
authors.forename: B M
authors.initials: BM
authors.lastname: von Blomberg
authors.forename: J P
authors.initials: JP
authors.lastname: van de Merwe
authors.forename: W L
authors.initials: WL
authors.lastname: Devillé
authors.forename: J C
authors.initials: JC
authors.lastname: Fonk
authors.forename: A S
authors.initials: AS
authors.lastname: Peña
mesh_terms: D019268:Antibodies, Antineutrophil Cytoplasmic; D000907:Antibodies, Bacterial / Q000097:blood; D001323:Autoantibodies / Q000097:blood; D015415:Biomarkers / Q000097:blood; D003093:Colitis, Ulcerative / Q000097:blood / Q000175:diagnosis*; D003424:Crohn Disease / Q000145:classification / Q000175:diagnosis*; D003937:Diagnosis, Differential; D005455:Fluorescent Antibody Technique; D016987:Gram-Positive Rods / Q000276:immunology; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D009161:Mycobacterium / Q000276:immunology; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012680:Sensitivity and Specificity
chemical_list: D019268:Antibodies, Antineutrophil Cytoplasmic; D000907:Antibodies, Bacterial; D001323:Autoantibodies; D015415:Biomarkers; D007074:Immunoglobulin G