Comparison of a salivary/sputum pepsin assay with 24-hour esophageal pH monitoring for detection of gastric reflux into the proximal esophagus, oropharynx, and lung

Dig Dis Sci. 2003 Sep;48(9):1813-7. doi: 10.1023/a:1025467600662.


The purpose of this study was to determine whether measurement of salivary/sputum pepsin could be used as a surrogate marker for detecting gastroesophageal reflux using 24-hr esophageal pH monitoring as the gold standard. Patients with gastroesophageal reflux symptoms underwent simultaneous 24-hr esophageal pH monitoring and collection of saliva and sputum samples for pepsin measurement using a recently developed assay. In all, 16 patients provided 19 positive (10.6%) and 161 negative pepsin assays. The mean pH values for the positive pepsin samples were lower then the negative samples at both the proximal [5.34 (95% CI, 4.94-5.75) vs 6.12 (95% CI, 6.03-6.20; P < 0.01)] and distal [4.97 (95% CI, 4.61-5.33) vs 6.03 (95% CI, 5.92-6.15; P < 0.01)] pH probes. Proximal esophageal reflux was not detected in patients who had a negative pepsin assay (N = 12); in contrast, proximal esophageal reflux was documented in three of four patients with a positive assay. In conclusion, detection of pepsin in the saliva and/or sputum may provide a noninvasive method to test for the proximal reflux of gastric contents.

Publication types

  • Comparative Study

MeSH terms

  • Esophagoscopy
  • Esophagus / chemistry
  • Female
  • Gastroesophageal Reflux / diagnosis*
  • Humans
  • Hydrogen-Ion Concentration
  • Male
  • Middle Aged
  • Monitoring, Physiologic
  • Pepsin A / analysis*
  • Saliva / chemistry*
  • Sensitivity and Specificity
  • Sputum / chemistry*


  • Pepsin A