title: Use of the lactose-[13C]ureide breath test for diagnosis of small bowel bacterial overgrowth: comparison to the glucose hydrogen breath test.
abstract: OBJECTIVE
  The glucose hydrogen breath test (GHBT) is commonly used as a noninvasive test to diagnose small bowel bacterial overgrowth (SBBO) but its validity has been questioned. Our aim was to evaluate the lactose-[(13)C]ureide breath test (LUBT) to diagnose SBBO and to compare it with the GHBT, using cultures of intestinal aspirates as a gold standard.
  
  
  METHODS
  In 22 patients with suspected SBBO (14 male, age range 18-73 years) aspirates were taken from the region of the ligament of Treitz under sterile conditions and cultured for bacterial growth. More than 10(6) colony-forming units/mL fluid or the presence of colonic flora was defined as culture positive (c+). After oral intake of 50 g glucose and 2 g of lactose-[(13)C]ureide, end-expiratory breath samples were obtained up to 120 min. The (13)C/(12)C ratio in breath CO(2) was determined by isotope ratio-mass spectrometry and hydrogen concentration in breath was analyzed electrochemically.
  
  
  RESULTS
  After analyzing receiver operating characteristic curves of the LUBT results, total label recovery of >0.88% at 120 min was considered positive. The test had a sensitivity of 66.7% and a specificity of 100% to predict c+. In the GHBT, an increase of the signal of > or =12 ppm from baseline was considered positive. The sensitivity and specificity of the test were 41.7 and 44.4%, respectively.
  
  
  CONCLUSIONS
  The new stable isotope-labeled LUBT has excellent specificity but suboptimal sensitivity. In contrast, the standard GHBT lacks both high sensitivity and specificity. The LUBT is superior to the GHBT for detecting SBBO.
authors: Department of Clinical Pharmacology, University of Bonn, Bonn, Germany. heiner.berthold@charite.de
authors: Heiner K
authors: HK
authors: Berthold
authors: Patrick
authors: P
authors: Schober
authors: Christian
authors: C
authors: Scheurlen
authors: Günter
authors: G
authors: Marklein
authors: Regine
authors: R
authors: Horré
authors: Ioanna
authors: I
authors: Gouni-Berthold
authors: Tilman
authors: T
authors: Sauerbruch
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001424:Bacterial Infections / Q000175:diagnosis*; D001944:Breath Tests / Q000379:methods; D005260:Female; D005947:Glucose; D006801:Humans; D006859:Hydrogen / Q000378:metabolism; D007421:Intestine, Small / Q000382:microbiology*; D007785:Lactose; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity; D014508:Urea / Q000031:analogs & derivatives*
chemical_list: C121442:lactose ureide; D006859:Hydrogen; D014508:Urea; D005947:Glucose; D007785:Lactose