title: Additional Value of CH₄ Measurement in a Combined (13)C/H₂ Lactose Malabsorption Breath Test: A Retrospective Analysis.
abstract: The lactose hydrogen breath test is a commonly used, non-invasive method for the detection of lactose malabsorption and is based on an abnormal increase in breath hydrogen (H₂) excretion after an oral dose of lactose. We use a combined (13)C/H₂ lactose breath test that measures breath (13)CO₂ as a measure of lactose digestion in addition to H₂ and that has a better sensitivity and specificity than the standard test. The present retrospective study evaluated the results of 1051 (13)C/H₂ lactose breath tests to assess the impact on the diagnostic accuracy of measuring breath CH₄ in addition to H₂ and (13)CO₂. Based on the (13)C/H₂ breath test, 314 patients were diagnosed with lactase deficiency, 138 with lactose malabsorption or small bowel bacterial overgrowth (SIBO), and 599 with normal lactose digestion. Additional measurement of CH₄ further improved the accuracy of the test as 16% subjects with normal lactose digestion and no H₂-excretion were found to excrete CH₄. These subjects should have been classified as subjects with lactose malabsorption or SIBO. In conclusion, measuring CH₄-concentrations has an added value to the (13)C/H₂ breath test to identify methanogenic subjects with lactose malabsorption or SIBO.
authors.affiliation: Translational Research Center for Gastrointestinal Disorders (TARGID), KU Leuven, Leuven 3000, Belgium. Els.Houben@uzleuven.be.|Clinical Department of Laboratory Medicine, University Hospitals Leuven, Leuven 3000, Belgium. Els.Houben@uzleuven.be.
authors.forename: Els
authors.initials: E
authors.lastname: Houben
authors.affiliation: Translational Research Center for Gastrointestinal Disorders (TARGID), KU Leuven, Leuven 3000, Belgium. Vicky.DePreter@ucll.be.|Group Health and Social Work, University College Leuven-Limburg (UCLL), Leuven 3000, Belgium. Vicky.DePreter@ucll.be.
authors.forename: Vicky
authors.initials: V
authors.lastname: De Preter
authors.affiliation: Clinical Department of Laboratory Medicine, University Hospitals Leuven, Leuven 3000, Belgium. Jaak.Billen@uzleuven.be.
authors.forename: Jaak
authors.initials: J
authors.lastname: Billen
authors.affiliation: Clinical Department of Laboratory Medicine, University Hospitals Leuven, Leuven 3000, Belgium. Marc.VanRanst@uzleuven.be.|Laboratory of Clinical and Epidemiological Virology, KU Leuven, Leuven 3000, Belgium. Marc.VanRanst@uzleuven.be.
authors.forename: Marc
authors.initials: M
authors.lastname: Van Ranst
authors.affiliation: Translational Research Center for Gastrointestinal Disorders (TARGID), KU Leuven, Leuven 3000, Belgium. Kristin.Verbeke@med.kuleuven.be.|Leuven Food Science and Nutrition Research Centre (LFoRCe), Leuven 3000, Belgium. Kristin.Verbeke@med.kuleuven.be.
authors.forename: Kristin
authors.initials: K
authors.lastname: Verbeke
mesh_terms: D000293:Adolescent; D000328:Adult; D015415:Biomarkers / Q000378:metabolism; D001765:Blind Loop Syndrome / Q000175:diagnosis* / Q000378:metabolism / Q000503:physiopathology; D001944:Breath Tests; D002245:Carbon Dioxide / Q000378:metabolism*; D004063:Digestion; D005260:Female; D006801:Humans; D006859:Hydrogen / Q000378:metabolism*; D007785:Lactose / Q000378:metabolism; D007787:Lactose Intolerance / Q000175:diagnosis* / Q000378:metabolism / Q000503:physiopathology; D008297:Male; D008697:Methane / Q000378:metabolism*; D008875:Middle Aged; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D015415:Biomarkers; D002245:Carbon Dioxide; D006859:Hydrogen; D007785:Lactose; D008697:Methane
keywords: breath test; hydrogen; lactase deficiency; lactose malabsorption; methane; stable isotopes