title: Semiquantitative assessment of breath hydrogen testing.
abstract: OBJECTIVE
  A major use of breath hydrogen testing is to assess absorptive capacity for sugars to assist dietary design for management of gut symptoms. Qualitative reporting takes no account of the vigor of hydrogen response and provides little insight into degrees of malabsorption. This study aimed to describe a semiquantitative reporting method and to compare results with those reported qualitatively.
  
  
  METHODS
  In consecutive Caucasian patients with Crohn's disease (n = 87), ulcerative colitis (59), functional gastrointestinal disorders (FGID) (162), and healthy controls (76), area under the curve was calculated for lactulose (15 g). This was compared with that for lactose (50 g) and fructose (35 g). Degree of malabsorption was categorized into arbitrary groups.
  
  
  RESULTS
  Semiquantitative results for ≥ 30% (designated "convincing") malabsorption was most similar to those using a qualitative cutoff value of 20 ppm, but in 38% and 21% of patients, the classification of malabsorption (nil or clinically significant) changed for fructose and lactose, respectively. Using a cutoff of 10 ppm, 49% and 5% were classified differently. Crohn's disease had a higher prevalence (42%) of convincing fructose malabsorption than controls (24%) or patients with FGID (33%) (P < 0.02). Highest prevalence of convincing lactose malabsorption (38%) was in ulcerative colitis, greater than controls (18%) and FGID (18%) (P < 0.02).
  
  
  CONCLUSIONS
  Semiquantitative assessment provides different results with different clinical implications in more than one third of patients, but disease-related alterations in prevalence are similar to those defined qualitatively. This method may be preferable because it lessens the confounding influence of the vigor of the hydrogen response.
authors.affiliation: Monash University, Eastern Health Clinical School, Box Hill, Victoria, Australia.
authors.forename: Jacqueline S
authors.initials: JS
authors.lastname: Barrett
authors.forename: Udaya
authors.initials: U
authors.lastname: Kalubovila
authors.forename: Peter M
authors.initials: PM
authors.lastname: Irving
authors.forename: Peter R
authors.initials: PR
authors.lastname: Gibson
mesh_terms: D000328:Adult; D001944:Breath Tests / Q000379:methods*; D016022:Case-Control Studies; D003093:Colitis, Ulcerative / Q000150:complications; D003424:Crohn Disease / Q000150:complications; D005260:Female; D005632:Fructose / Q000493:pharmacokinetics; D005767:Gastrointestinal Diseases / Q000150:complications; D006801:Humans; D006859:Hydrogen / Q000032:analysis*; D007785:Lactose / Q000493:pharmacokinetics; D007787:Lactose Intolerance / Q000175:diagnosis / Q000209:etiology; D007792:Lactulose / Q000493:pharmacokinetics; D008286:Malabsorption Syndromes / Q000175:diagnosis* / Q000209:etiology; D008297:Male; D008875:Middle Aged
chemical_list: D005632:Fructose; D007792:Lactulose; D006859:Hydrogen; D007785:Lactose
keywords: IBD: clinical trials < gastroenterology; diarrhea and malabsorption < gastroenterology; functional disorders < gastroenterology