title: Normal 24-hour Ambulatory Esophageal pH Values in Koreans.
abstract: OBJECTIVE
  Twenty-four-hour ambulatory esophageal pH monitoring is considered the gold standard for diagnosing gastroesophageal reflux disease. The aim of this study was to quantify normal distal esophageal acid parameters in healthy Koreans.
  
  
  METHODS
  Thirty healthy adults who were not on medication and were free from gastrointestinal symptoms were analyzed. Ambulatory esophageal acid (pH <4) exposure parameters were recorded at 5 cm above the lower esophageal sphincter.
  
  
  RESULTS
  The 95th percentiles for reflux parameters assessed in the distal esophagus were as follows: percentage of total time with pH <4, 5.10%; percentage of upright time with pH <4, 7.88%; percentage of supine time with pH <4, 4.00%; number of reflux episodes, 62.7; number of reflux episodes with pH <4 for >5 minutes, 5.3; and the longest single acid-exposure episode, 21.3 minutes.
  
  
  CONCLUSIONS
  Physiological gastroesophageal reflux occurs frequently in healthy Koreans. These data provide a reference range that could be utilized in studies involving Korean subjects.
authors.affiliation: Department of Internal Medicine, Kosin University College of Medicine, Busan, Korea.
authors.forename: Won
authors.initials: W
authors.lastname: Moon
authors.forename: Moo In
authors.initials: MI
authors.lastname: Park
authors.forename: Gyung Mi
authors.initials: GM
authors.lastname: Kim
authors.forename: Kyu Jong
authors.initials: KJ
authors.lastname: Kim
authors.forename: Seun Ja
authors.initials: SJ
authors.lastname: Park
authors.forename: Hyo Sung
authors.initials: HS
authors.lastname: Mun
authors.forename: Kang Dae
authors.initials: KD
authors.lastname: Lee