From sponges to capsules. The history of esophageal pH monitoring.

The understanding of digestive physiology, gastric acid production, and gastroesophageal reflux disease has been evolving since the 16th century. During this time, several methods to detect gastric refluxate were ingeniously developed. Ambulatory esophageal pH monitoring is still the current gold standard test for the diagnosis of gastroesophageal reflux disease. State-of-the-art technologies use catheter-free wireless pH sensors, an idea first conceived in the 1950s. The authors reviewed the history of esophageal pH monitoring.