The MOST sensitive test to diagnose GERD is:
Gastroesophageal Reflux Disease (GERD) Classic symptoms of gastroesophageal reflux are - water brash and substernal heaburn. Endoscopy is a sensitive test for diagnosis of esophagitis but will miss nonerosive reflux disease (NERD) MUST KNOW: The most sensitive test for diagnosis is 24-h ambulatory pH monitoring. Ref: Harrison, Edition-18, Page-2417.
24 hour ambulatory pH monitoring
Upper GI endoscopy
Basal acid output measurement
Bernstein test