title: Does the diagnostic accuracy of the 13C-urea breath test vary with age even after the application of urea hydrolysis rate?
abstract: BACKGROUND
  Endogenous CO(2) production may be a possible explanation for higher false-positive results reported for (13)C-urea breath test (UBT) in children below 6 years. In this study, we evaluated whether age affects the diagnostic accuracy of the (13)C-UBT even after the application of urea hydrolysis rate (UHR) in children.
  
  
  METHODS
  A total of 612 (13)C-UBTs and endoscopic biopsies were performed on children divided into two groups; children under 6 years (n = 126) and children aged 6-18 years (n = 486). For (13)C-UBT, 75 mg (13)C-urea was ingested, and breath sample was collected 30 minutes later. Delta over baseline (DOB) was determined, and UHR was calculated to normalize the DOB values for endogenous CO(2) production.
  
  
  RESULTS
  There was significant difference between the DOB values of children under 6 years and those of children over 6 years in H. pylori-positive (p = .029) and -negative groups (p = .002). On applying the UHR, no significant difference was observed between the UHR values of children under 6 years and those of children over 6 years in H. pylori-positive (p = .877) and -negative groups (p = .427). In 12.6% children under 6 years, false-positive results were observed on applying the DOB, and in 9.0% on applying the UHR (p = .125).
  
  
  CONCLUSIONS
  The (13)C-UBT is a noninvasive method exhibiting high diagnostic accuracy with both UHR as well as DOB. However, high false-positive results for (13)C-UBT were noted in children below 6 years on applying both UHR as well as DOB. Thus, this may not only be due to the effects of endogenous CO(2) production but also due to other factors.
authors.affiliation: Department of Pediatrics, Seoul National University College of Medicine, Seoul, South Korea.
authors.forename: Hye Ran
authors.initials: HR
authors.lastname: Yang
authors.forename: Jae Sung
authors.initials: JS
authors.lastname: Ko
authors.forename: Jeong Kee
authors.initials: JK
authors.lastname: Seo
mesh_terms: D000293:Adolescent; D000367:Age Factors; D001426:Bacterial Proteins / Q000378:metabolism; D001944:Breath Tests / Q000379:methods*; D002138:Calibration; D002247:Carbon Isotopes / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D016099:Endoscopy, Gastrointestinal; D005189:False Positive Reactions; D005260:Female; D016481:Helicobacter Infections / Q000175:diagnosis* / Q000378:metabolism / Q000382:microbiology* / Q000473:pathology; D016480:Helicobacter pylori / Q000302:isolation & purification / Q000378:metabolism*; D006801:Humans; D006868:Hydrolysis; D007223:Infant; D008297:Male; D014508:Urea / Q000032:analysis* / Q000378:metabolism; D014510:Urease / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D002247:Carbon Isotopes; D014508:Urea; D014510:Urease