Gastroesophageal pH step-up inaccurately locates proximal border of lower esophageal sphincter

Dig Dis Sci. 1992 Aug;37(8):1185-91. doi: 10.1007/BF01296558.


Limiting the widespread use of 24-hr pH monitoring is the necessity of manometrically placing the pH probe 5 cm above the proximal lower esophageal sphincter (LES) border. Therefore, we prospectively compared LES localization by gastroesophageal pH step-up with manometry in 71 patients and 14 asymptomatic volunteers. The gastroesophageal pH step-up significantly correlated with the proximal LES border in patients (r = 0.53, P less than 0.0001) and volunteers (r = 0.91, P less than 0.0001). Based on previously published criteria, the pH step-up value was considered acceptably accurate if it was within +/- 3 cm (6 cm total span) of the manometrically determined proximal LES border. In 58% of patients and 29% of volunteers the pH step-up occurred outside this accuracy range. Esophagitis (P = 0.015) and abnormal reflux parameters (P = 0.002) were variables contributing to this error. Subsequent analysis found that the pH step-up overestimated the proximal LES border and occurred at the midportion of the sphincter. The pH step-up still inaccurately located the mid LES in 34% of patients. Therefore, manometry should remain the standard for accurate LES localization prior to placing the pH probe.

Publication types

  • Comparative Study

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Chi-Square Distribution
  • Circadian Rhythm / physiology
  • Confidence Intervals
  • Esophagogastric Junction / physiopathology*
  • Female
  • Gastroesophageal Reflux / epidemiology
  • Gastroesophageal Reflux / physiopathology
  • Humans
  • Hydrogen-Ion Concentration
  • Male
  • Manometry / instrumentation
  • Manometry / methods
  • Manometry / statistics & numerical data
  • Middle Aged
  • Monitoring, Physiologic / instrumentation
  • Monitoring, Physiologic / methods
  • Monitoring, Physiologic / statistics & numerical data
  • Prospective Studies
  • Regression Analysis
  • Reproducibility of Results