title: Four-sample lactose hydrogen breath test for diagnosis of lactose malabsorption in irritable bowel syndrome patients with diarrhea.
abstract: OBJECTIVE
  To validate 4-sample lactose hydrogen breath testing (4SLHBT) compared to standard 13-sample LHBT in the clinical setting.
  
  
  METHODS
  Irritable bowel syndrome patients with diarrhea (IBS-D) and healthy volunteers (HVs) were enrolled and received a 10 g, 20 g, or 40 g dose lactose hydrogen breath test (LHBT) in a randomized, double-blinded, controlled trial. The lactase gene promoter region was sequenced. Breath samples and symptoms were acquired at baseline and every 15 min for 3 h (13 measurements). The detection rates of lactose malabsorption (LM) and lactose intolerance (LI) for a 4SLHBT that acquired four measurements at 0, 90, 120, and 180 min from the same data set were compared with the results of standard LHBT.
  
  
  RESULTS
  Sixty IBS-D patients and 60 HVs were studied. The genotype in all participants was C/C-13910. LM and LI detection rates increased with lactose dose from 10 g, 20 g to 40 g in both groups (P < 0.001). 4SLHBT showed excellent diagnostic concordance with standard LHBT (97%-100%, Kappa​​ 0.815-0.942) with high sensitivity (90%-100%) and specificity (100%) at all three lactose doses in both groups.
  
  
  CONCLUSIONS
  Reducing the number of measurements from 13 to 4 samples did not significantly impact on the accuracy of LHBT in health and IBS-D. 4SLHBT is a valid test for assessment of LM and LI in clinical practice.
authors.affiliation: Jian-Feng Yang, Department of Gastroenterology, The First People's Hospital of Hangzhou, Hangzhou 310016, Zhejiang Province, China.
authors.forename: Jian-Feng
authors.initials: JF
authors.lastname: Yang
authors.affiliation: Jian-Feng Yang, Department of Gastroenterology, The First People's Hospital of Hangzhou, Hangzhou 310016, Zhejiang Province, China.
authors.forename: Mark
authors.initials: M
authors.lastname: Fox
authors.affiliation: Jian-Feng Yang, Department of Gastroenterology, The First People's Hospital of Hangzhou, Hangzhou 310016, Zhejiang Province, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Chu
authors.affiliation: Jian-Feng Yang, Department of Gastroenterology, The First People's Hospital of Hangzhou, Hangzhou 310016, Zhejiang Province, China.
authors.forename: Xia
authors.initials: X
authors.lastname: Zheng
authors.affiliation: Jian-Feng Yang, Department of Gastroenterology, The First People's Hospital of Hangzhou, Hangzhou 310016, Zhejiang Province, China.
authors.forename: Yan-Qin
authors.initials: YQ
authors.lastname: Long
authors.affiliation: Jian-Feng Yang, Department of Gastroenterology, The First People's Hospital of Hangzhou, Hangzhou 310016, Zhejiang Province, China.
authors.forename: Daniel
authors.initials: D
authors.lastname: Pohl
authors.affiliation: Jian-Feng Yang, Department of Gastroenterology, The First People's Hospital of Hangzhou, Hangzhou 310016, Zhejiang Province, China.
authors.forename: Michael
authors.initials: M
authors.lastname: Fried
authors.affiliation: Jian-Feng Yang, Department of Gastroenterology, The First People's Hospital of Hangzhou, Hangzhou 310016, Zhejiang Province, China.
authors.forename: Ning
authors.initials: N
authors.lastname: Dai
mesh_terms: D015415:Biomarkers / Q000378:metabolism; D001944:Breath Tests; D002681:China; D018592:Cross-Over Studies; D003967:Diarrhea / Q000175:diagnosis / Q000209:etiology*; D004311:Double-Blind Method; D020022:Genetic Predisposition to Disease; D006801:Humans; D006859:Hydrogen / Q000378:metabolism*; D043183:Irritable Bowel Syndrome / Q000150:complications* / Q000175:diagnosis; D043322:Lactase / Q000172:deficiency / Q000235:genetics; D007785:Lactose / Q000008:administration & dosage / Q000378:metabolism*; D007787:Lactose Intolerance / Q000150:complications / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism; D020641:Polymorphism, Single Nucleotide; D011237:Predictive Value of Tests; D011401:Promoter Regions, Genetic; D015203:Reproducibility of Results; D013997:Time Factors
chemical_list: D015415:Biomarkers; D006859:Hydrogen; D043322:Lactase; D007785:Lactose
keywords: Diagnosis; Irritable bowel syndrome; Lactose hydrogen breath test; Lactose intolerance; Lactose malabsorption