Wireless 24, 48, and 96 Hour or Impedance or Oropharyngeal Prolonged pH Monitoring: Which Test, When, and Why for GERD?

  • Soojong Chae
  • Joel E. RichterEmail author
Neurogastroenterology and Motility Disorders of the Gastrointestinal Tract (S Rao, Section Editor)
Part of the following topical collections:
  1. Topical Collection on Neurogastroenterology and Motility Disorders of the Gastrointestinal Tract


Purpose of Review

pH monitoring technologies are routinely utilized in practice to further evaluate symptoms of gastro-esophageal reflux disease and laryngopharyngeal reflux (LPR). This is a review of the recent literature of the available pH monitoring technology and creates an algorithm in the diagnostic work up of a patient with GERD or LPR.

Recent Findings

The catheter-free wireless pH monitor traditionally collects data for 48 h. Recent studies have found that extending to 96 h can be helpful in patients with conflicting results on the first 2 days of the study. In addition, 96 h can allow for testing both on and off of PPI therapy. The oropharyngeal monitoring device is a newer technology that is designed to aid in the diagnoses of LPR. There are limitations with this technology as there is no universal abnormal cutoff and some studies have suggested a poor correlation between multichannel intraluminal impedance-pH (MII-pH) and the oropharyngeal monitoring device. MII-pH has recently developed two additional parameters, the measurement of three 10-min nighttime periods and the post-reflux swallow-induced peristaltic wave (PSPW) index, both of which may increase accuracy of testing.


Each of these technologies can provide unique data regarding acid reflux exposure in the esophagus and oropharynx. The wireless pH monitor performed off of PPI therapy can help to establish or exclude the diagnosis of GERD. For those patients with refractory symptoms on PPI, MII-pH study can be performed while on therapy and provides data regarding the response to treatment. Oropharyngeal pH monitoring is being utilized in some practices to aid in diagnosis of LPR, but the scientific validity is controversial.


Wireless pH monitor Oropharyngeal pH monitor Impedance pH test Weak acid reflux Gastroesophageal reflux disease 


Compliance with Ethical Standards

Conflict of Interest

Soojong Chae and Joel Richter declare no conflict of interest. Dr. Richter is the Editor in Chief of Current Gastroenterology Reports, but this paper was reviewed by Section Editor Satish Rao.

Human and Animal Rights and Informed Consent

This article does not contain any studies with human or animal subjects performed by any of the authors.


Papers of particular interest, published recently, have been highlighted as: • Of importance •• Of major importance

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Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature 2018

Authors and Affiliations

  1. 1.The Joy McCann Culverhouse Center for Esophageal Diseases, Division of Digestive Diseases and NutritionUniversity of South Florida, Morsani College of MedicineTampaUSA

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