title: Analysis of Exhaled Breath Volatile Organic Compounds in Inflammatory Bowel Disease: A Pilot Study.
abstract: OBJECTIVE
  Distinguishing between the inflammatory bowel diseases [IBD], Crohn's disease [CD] and ulcerative colitis [UC], is important for determining management and prognosis. Selected ion flow tube mass spectrometry [SIFT-MS] may be used to analyse volatile organic compounds [VOCs] in exhaled breath: these may be altered in disease states, and distinguishing breath VOC profiles can be identified. The aim of this pilot study was to identify, quantify, and analyse VOCs present in the breath of IBD patients and controls, potentially providing insights into disease pathogenesis and complementing current diagnostic algorithms.
  
  
  METHODS
  SIFT-MS breath profiling of 56 individuals [20 UC, 18 CD, and 18 healthy controls] was undertaken. Multivariate analysis included principal components analysis and partial least squares discriminant analysis with orthogonal signal correction [OSC-PLS-DA]. Receiver operating characteristic [ROC] analysis was performed for each comparative analysis using statistically significant VOCs.
  
  
  RESULTS
  OSC-PLS-DA modelling was able to distinguish both CD and UC from healthy controls and from one other with good sensitivity and specificity. ROC analysis using combinations of statistically significant VOCs [dimethyl sulphide, hydrogen sulphide, hydrogen cyanide, ammonia, butanal, and nonanal] gave integrated areas under the curve of 0.86 [CD vs healthy controls], 0.74 [UC vs healthy controls], and 0.83 [CD vs UC].
  
  
  CONCLUSIONS
  Exhaled breath VOC profiling was able to distinguish IBD patients from controls, as well as to separate UC from CD, using both multivariate and univariate statistical techniques.
authors.affiliation: Gastroenterology & Hepatology Section, Department of Medicine, Imperial College London, London UK.
authors.forename: Lucy C
authors.initials: LC
authors.lastname: Hicks
authors.affiliation: Department of Surgery and Cancer, Imperial College London, London UK.
authors.forename: Juzheng
authors.initials: J
authors.lastname: Huang
authors.affiliation: Department of Surgery and Cancer, Imperial College London, London UK.
authors.forename: Sacheen
authors.initials: S
authors.lastname: Kumar
authors.affiliation: Gastroenterology & Hepatology Section, Department of Medicine, Imperial College London, London UK.
authors.forename: Sam T
authors.initials: ST
authors.lastname: Powles
authors.affiliation: Gastroenterology & Hepatology Section, Department of Medicine, Imperial College London, London UK.
authors.forename: Timothy R
authors.initials: TR
authors.lastname: Orchard
authors.affiliation: Department of Surgery and Cancer, Imperial College London, London UK.
authors.forename: George B
authors.initials: GB
authors.lastname: Hanna
authors.affiliation: Gastroenterology & Hepatology Section, Department of Medicine, Imperial College London, London UK.
authors.forename: Horace R T
authors.initials: HR
authors.lastname: Williams
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000378:metabolism; D001944:Breath Tests; D016022:Case-Control Studies; D003093:Colitis, Ulcerative / Q000175:diagnosis* / Q000378:metabolism; D003424:Crohn Disease / Q000175:diagnosis* / Q000378:metabolism; D003937:Diagnosis, Differential; D016002:Discriminant Analysis; D005260:Female; D006801:Humans; D008297:Male; D013058:Mass Spectrometry / Q000379:methods; D008875:Middle Aged; D015233:Models, Statistical; D010865:Pilot Projects; D025341:Principal Component Analysis; D012372:ROC Curve; D012680:Sensitivity and Specificity; D055549:Volatile Organic Compounds / Q000378:metabolism*
chemical_list: D015415:Biomarkers; D055549:Volatile Organic Compounds
keywords: Volatile organic compounds; breath; inflammatory bowel disease; metabonomics