system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
GERD is best diagnosed by?
assistant
The correct answer is  Ans. (a) 24 hour pH monitoringRef.: Harrison 19th ed. / 261-2* Ambulatory 24-hour pH monitoring is the criterion standard in establishing a diagnosis of GERD, with a sensitivity of 96% and a specificity of 95%. It quantifies the gastroesophageal reflux and allows a correlation between the symptoms of reflux and the episodes of reflux.* However the diagnosis can be established on basis of Upper Gastrointestinal endoscopy with esophageal manometry.