title: Clinical utility and diagnostic accuracy of faecal calprotectin for IBD at first presentation to gastroenterology services in adults aged 16-50 years.
abstract: BACKGROUND
  Distinguishing inflammatory bowel disease (IBD) from functional gastrointestinal (GI) disease remains an important issue for gastroenterologists and primary care physicians, and may be difficult on the basis of symptoms alone. Faecal calprotectin (FC) is a surrogate marker for intestinal inflammation but not cancer.
  
  
  OBJECTIVE
  This large retrospective study aimed to determine the most effective use of FC in patients aged 16-50 presenting with GI symptoms.
  
  
  METHODS
  FC results were obtained for patients presenting to the GI clinics in Edinburgh between 2005 and 2009 from the Edinburgh Faecal Calprotectin Registry containing FCs from >16,000 patients. Case notes were interrogated to identify demographics, subsequent investigations and diagnoses.
  
  
  RESULTS
  895 patients were included in the main analysis, 65% female and with a median age of 33 years. 10.2% were diagnosed with IBD, 7.3% with another GI condition associated with an abnormal GI tract and 63.2% had functional GI disease. Median FC in these three groups were 1251, 50 and 20 μg/g (p < 0.0001). On ROC analysis, the AUC for FC as a predictor of IBD vs. functional disease was 0.97. Using a threshold of ≥ 50 μg/g for IBD vs. functional disease yielded a sensitivity of 0.97, specificity of 0.74, positive predictive value of 0.37 and negative predictive value of 0.99. Combined with alarm symptoms, the sensitivity was 1.00.
  
  
  CONCLUSIONS
  Implementation of FC in the initial diagnostic workup of young patients with GI symptoms, particularly those without alarm symptoms, is highly accurate in the exclusion of IBD, and can provide reassurance to patients and physicians.
authors.affiliation: Gastrointestinal Unit, Western General Hospital, Edinburgh, UK.
authors.forename: Nicholas A
authors.initials: NA
authors.lastname: Kennedy
authors.affiliation: Gastrointestinal Unit, Western General Hospital, Edinburgh, UK.
authors.forename: Annalie
authors.initials: A
authors.lastname: Clark
authors.affiliation: Gastrointestinal Unit, Western General Hospital, Edinburgh, UK.
authors.forename: Andrew
authors.initials: A
authors.lastname: Walkden
authors.affiliation: Gastrointestinal Unit, Western General Hospital, Edinburgh, UK.
authors.forename: Jeff C W
authors.initials: JC
authors.lastname: Chang
authors.affiliation: Gastrointestinal Unit, Western General Hospital, Edinburgh, UK.
authors.forename: Federica
authors.initials: F
authors.lastname: Fascí-Spurio
authors.affiliation: Gastrointestinal Unit, Western General Hospital, Edinburgh, UK.
authors.forename: Martina
authors.initials: M
authors.lastname: Muscat
authors.affiliation: Department of Clinical Biochemistry, Western General Hospital, Edinburgh, UK.
authors.forename: Brydon W
authors.initials: BW
authors.lastname: Gordon
authors.affiliation: Department of Clinical Biochemistry, Western General Hospital, Edinburgh, UK.
authors.forename: Kathleen
authors.initials: K
authors.lastname: Kingstone
authors.affiliation: Gastrointestinal Unit, Western General Hospital, Edinburgh, UK.
authors.forename: Jack
authors.initials: J
authors.lastname: Satsangi
authors.affiliation: Gastrointestinal Unit, Western General Hospital, Edinburgh, UK.
authors.forename: Ian D R
authors.initials: ID
authors.lastname: Arnott
authors.affiliation: Gastrointestinal Unit, Western General Hospital, Edinburgh, UK charlie.lees@ed.ac.uk.
authors.forename: Charlie W
authors.initials: CW
authors.lastname: Lees
mesh_terms: D000293:Adolescent; D000328:Adult; D003113:Colonoscopy; D004797:Enzyme-Linked Immunosorbent Assay; D005243:Feces / Q000737:chemistry*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000175:diagnosis* / Q000378:metabolism; D039841:Leukocyte L1 Antigen Complex / Q000032:analysis*; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012720:Severity of Illness Index; D055815:Young Adult
chemical_list: D039841:Leukocyte L1 Antigen Complex
keywords: Crohn’s disease; Diagnostic test; Faecal calprotectin; Inflammatory bowel disease; Sensitivity; Ulcerative colitis