A 45-year-old lady presents with persistent reflux symptoms. The most accurate investigation in establishing diagnosis before surgical treatment includes

investigations for GASTROESOPHAGEAL REFLUX DISEASE, *24 hours oesophageal pH monitoring - the gold standard. PPI should be stopped for 3 weeks prior to pH monitoring. *Barium study in head down position. * Endoscopy to exclude other disease and to assess any mucosal injury - red inflamed mucosa often with ulceration. Sliding hernia can be identified through endoscopy. When patient retches, gastric mucosa will enter the OG junction and ascends upwards to variable distance. Ref: SRB&;s manual of surgery,3 rd ed, pg no 723