title: Breath Hydrogen as a Biomarker for Glucose Malabsorption after Roux-en-Y Gastric Bypass Surgery.
abstract: OBJECTIVE
  Abdominal symptoms are common after bariatric surgery, and these individuals commonly have upper gut bacterial overgrowth, a known cause of malabsorption. Breath hydrogen determination after oral glucose is a safe and inexpensive test for malabsorption. This study is designed to investigate breath hydrogen levels after oral glucose in symptomatic individuals who had undergone Roux-en-Y gastric bypass surgery.
  
  
  METHODS
  This is a retrospective study of individuals (n = 63; 60 females; 3 males; mean age 49 years) who had gastric bypass surgery and then glucose breath testing to evaluate abdominal symptoms.
  
  
  RESULTS
  Among 63 postoperative individuals, 51 (81%) had a late rise (≥45 minutes) in breath hydrogen or methane, supporting glucose malabsorption; 46 (90%) of these 51 subjects also had an early rise (≤30 minutes) in breath hydrogen or methane supporting upper gut bacterial overgrowth. Glucose malabsorption was more frequent in subjects with upper gut bacterial overgrowth compared to subjects with no evidence for bacterial overgrowth (P < 0.001).
  
  
  CONCLUSIONS
  These data support the presence of intestinal glucose malabsorption associated with upper gut bacterial overgrowth in individuals with abdominal symptoms after gastric bypass surgery. Breath hydrogen testing after oral glucose should be considered to evaluate potential malabsorption in symptomatic, postoperative individuals.
authors.affiliation: Department of Medicine, MedStar-Washington Hospital Center and Georgetown University School of Medicine, Washington, DC 20010, USA.
authors.forename: Iman
authors.initials: I
authors.lastname: Andalib
authors.affiliation: EPGI, Allentown, PA 18104, USA.
authors.forename: Hiral
authors.initials: H
authors.lastname: Shah
authors.affiliation: Center for Gastrointestinal and Liver Diseases, Centra Southside, Farmville, VA 23901, USA.
authors.forename: Bikram S
authors.initials: BS
authors.lastname: Bal
authors.affiliation: Department of Surgery and Center for Advanced Laparoscopic & Bariatric Surgery, MedStar-Washington Hospital Center and Georgetown University School of Medicine, Washington, DC 20010, USA.
authors.forename: Timothy R
authors.initials: TR
authors.lastname: Shope
authors.affiliation: Department of Surgery and Center for Advanced Laparoscopic & Bariatric Surgery, MedStar-Washington Hospital Center and Georgetown University School of Medicine, Washington, DC 20010, USA.
authors.forename: Frederick C
authors.initials: FC
authors.lastname: Finelli
authors.affiliation: Department of Surgery and Center for Advanced Laparoscopic & Bariatric Surgery, MedStar-Washington Hospital Center and Georgetown University School of Medicine, Washington, DC 20010, USA.
authors.forename: Timothy R
authors.initials: TR
authors.lastname: Koch
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000032:analysis; D001944:Breath Tests / Q000379:methods*; D002239:Carbohydrate Metabolism, Inborn Errors / Q000175:diagnosis* / Q000209:etiology; D005260:Female; D015390:Gastric Bypass / Q000009:adverse effects*; D006801:Humans; D006859:Hydrogen / Q000032:analysis*; D007422:Intestines / Q000382:microbiology; D008286:Malabsorption Syndromes / Q000175:diagnosis* / Q000209:etiology; D008297:Male; D008697:Methane / Q000032:analysis; D008875:Middle Aged
chemical_list: D015415:Biomarkers; D006859:Hydrogen; D008697:Methane