title: [Correlation between the presence and intensity of symptoms and the results of hydrogen breath tests in the diagnosis of carbohydrate intolerance].
abstract: BACKGROUND
  Hydrogen breath tests (HBT) are used to confirm the diagnosis of carbohydrate intolerance or small intestinal bacterial overgrowth (SIBO).
  
  
  OBJECTIVE
  Determine the existence of a correlation between the presence and intensity of symptoms experimented by the patient after the ingestion of a carbohydrate load and the test result.
  
  
  METHODS
  This is an observational, retrospective and analytic study, in which all patients' files from year 2008 to 2014 containing a report of a HBT performed at Hospital San José TEC de Monterrey were revised. Using a visual analogue scale (VAS), the patient reported the intensity of gastrointestinal symptoms during the test. Descriptive statistics were obtained, and exclusively for lactose HBTs, Pearson's correlation coefficient (r) between maximum hydrogen concentration in breath and symptom intensity was calculated.
  
  
  RESULTS
  A HBT was performed in 33 patients: 23 with lactose, 5 with fructose, and 5 with lactulose as substrate. Of these, 10, 2, and 5 tests were positive, respectively. For lactose HBTs, the symptom with most sensitivity was flatulence (80%), which also had the greatest likelihood ratio for a positive test (1.73). Diarrhea had the greatest specificity (84.6%). A tendency for positivity was observed when patients presented symptoms. A moderately positive correlation between hydrogen ppm and symptom intensity was found (r=0.427, p=0.023).
  
  
  CONCLUSIONS
  A correlation between symptom intensity and test positivity was found in patients with lactose intolerance. The presence of flatulence after lactose loading may be indicative of a positive test.
authors.affiliation: Escuela de Medicina, Tecnológico de Monterrey. Monterrey, Nuevo León, México.
authors.forename: María Teresa
authors.initials: MT
authors.lastname: Sánchez-Ávila
authors.affiliation: Escuela de Medicina, Tecnológico de Monterrey. Monterrey, Nuevo León, México.
authors.forename: Karla Lorena
authors.initials: KL
authors.lastname: Chávez Caraza
authors.affiliation: Escuela de Medicina, Tecnológico de Monterrey. Monterrey, Nuevo León, México.
authors.forename: Adrián Marcelo
authors.initials: AM
authors.lastname: González Gil
authors.affiliation: Escuela de Medicina, Tecnológico de Monterrey. Monterrey, Nuevo León, México.
authors.forename: Jaime Javier
authors.initials: JJ
authors.lastname: Cantú Pompa
authors.affiliation: Escuela de Medicina, Tecnológico de Monterrey. Monterrey, Nuevo León, México.
authors.forename: Edgar
authors.initials: E
authors.lastname: Moreno Medrano
authors.affiliation: Escuela de Medicina, Tecnológico de Monterrey. Monterrey, Nuevo León, México.
authors.forename: Luis Alonso
authors.initials: LA
authors.lastname: Morales-Garza
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000378:metabolism; D001944:Breath Tests; D002648:Child; D002675:Child, Preschool; D005260:Female; D005414:Flatulence / Q000209:etiology; D005633:Fructose Intolerance / Q000175:diagnosis* / Q000378:metabolism; D006801:Humans; D006859:Hydrogen / Q000378:metabolism*; D007223:Infant; D007787:Lactose Intolerance / Q000175:diagnosis* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D055815:Young Adult
chemical_list: D015415:Biomarkers; D006859:Hydrogen