title: Fecal calprotectin is an effective diagnostic tool that differentiates inflammatory from functional intestinal disorders.
abstract: BACKGROUND
  The clinical pictures of functional gastrointestinal disorders and inflammatory diseases can be quite similar leading to inappropriate and expensive investigations. Objective. To investigate fecal calprotectin (FC) diagnostic performance in different gastrointestinal conditions.
  
  
  METHODS
  Stool specimens of 66 outpatients referred for colonoscopy were collected for further FC determination. Diagnostic accuracy was assessed by the area under the curve (AUC). Sensitivity (Se), specificity (Sp), positive (PPV), and negative predictive values (NPV) were calculated according to the presence of inflammation and the main final diagnosis.
  
  
  RESULTS
  Histological inflammation was found in 45 (68%) patients: 24 had a diagnosis of inflammatory bowel disease (IBD) while 21 reported miscellaneous conditions (5 microscopic colitis, 2 eosinophilic colitis, and 14 nonspecific chronic colitis). The diagnosis in the 21 (32%) patients without inflammation was irritable bowel syndrome (IBS). Median FC values were 268 µg/g (95% CI, 151-343) and 49 µg/g (95% CI, 23-101) in patients with and without inflammation, respectively (p = 0.0001). AUC value of FC was 0.811 (Se = 68.9%, Sp = 71.4%, PPV = 83.8%, and NPV = 56.3% with a cutoff value of 100 µg/g) for discriminating between patients with and without inflammation and 0.931 (Se = 87.5%, Sp = 90.5%, PPV = 91.3%, and NPV = 86.4% with a cutoff value of 150 µg/g) for discriminating between patients with IBS and IBD. Using the cutoff value recommended by the manufacturer (50 µg/g), we found Se =100%, Sp =52.4%, PPV =70.6%, and NPV =100% for the diagnosis of IBD.
  
  
  CONCLUSIONS
  FC appears to be a reliable noninvasive biomarker of intestinal inflammation useful to improve the appropriateness of colonoscopy requests.
authors.affiliation: Department of Medical Sciences, University of Turin , Turin , Italy.
authors.forename: Gian Paolo
authors.initials: GP
authors.lastname: Caviglia
authors.forename: Stefano
authors.initials: S
authors.lastname: Pantaleoni
authors.forename: Giovanni Antonio
authors.initials: GA
authors.lastname: Touscoz
authors.forename: Alessandro
authors.initials: A
authors.lastname: Adriani
authors.forename: Chiara
authors.initials: C
authors.lastname: Rosso
authors.forename: Antonina
authors.initials: A
authors.lastname: Smedile
authors.forename: Rinaldo
authors.initials: R
authors.lastname: Pellicano
authors.forename: Marco
authors.initials: M
authors.lastname: Astegiano
authors.forename: Francesca
authors.initials: F
authors.lastname: Bresso
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000378:metabolism; D003113:Colonoscopy; D003937:Diagnosis, Differential; D005243:Feces / Q000737:chemistry*; D005260:Female; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000175:diagnosis* / Q000378:metabolism; D043183:Irritable Bowel Syndrome / Q000175:diagnosis* / Q000378:metabolism; D039841:Leukocyte L1 Antigen Complex / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity; D055815:Young Adult
chemical_list: D015415:Biomarkers; D039841:Leukocyte L1 Antigen Complex
keywords: fecal calprotectin; inflammatory bowel disease-clinical; irritable bowel syndrome