Best test to diagnose gastroesophageal reflux disease and quantify acid output is:
24 hr pH monitoring "The gold standard, for diagnosing and quantifying acid reflux is the 24-hr pH test." -Sabiston Also Know Using 24-hour pH test an overall score is obtained. It is known as DeMeester score.
Esohagogram
Endoscopy
Manometry
24 hr pH monitoring