Oesophageal pH testing: everything you wanted to know but were too afraid to ask

Reflux of gastric content into the oesophagus is a normal physiological phenomenon, but in the context of troublesome symptoms including heartburn, regurgitation and/or oesophageal chest pain, it is denoted gastro-oesophageal reflux disease (GORD). Unfortunately, many patients do not respond adequately to acid suppression therapy leading to overprescription of proton pump inhibitors (PPIs), major healthcare costs and reduced quality of life. Most patients with reflux have a normal endoscopy, which means oesophageal pH testing becomes critical to determine the role of reflux on symptoms. Oesophageal pH testing can be catheter-based or wireless, and modern impedance catheters provide additional adjunctive information to support the diagnosis. In this educational review, we cover the fundamental aspects of when, how and why to organise oesophageal pH testing. We then discuss how testing is used to determine reflux phenotypes, which in turn are essential to guide clinical decision-making in the management of PPI-refractory GORD.