Medicine C.V.S 11682977 The gold standard for diagnosis of gastroesophageal reflux disease (GERD) is A Endoscopy B Barium swallow C Esophageal manometry D 24-hours ambulatory pH monitoring High-Yield Explanation The most sensitive test for diagnosis of GERD is 24-h ambulatory pH monitoringRef: Harrison; 19th edition; Page no: 1894