An OGD (‘gastroscopy’ or ‘upper gastrointestinal endoscopy’) examines the gullet (oesophagus), stomach and duodenum. The endoscope is passed through the mouth. The procedure is usually carried out after local anaesthetic throat spray or intravenous sedation (with a benzodiazepine).

This test involves passing the endoscope through the back passage (rectum) to examine the whole colon (large intestine, or bowel). It is normally carried out under intravenous sedation (with a benzodiazepine and opioid agent). Alternatively, Entonox ( a gas) inhaled through a mouthpiece may be suitable for some patients to undergo the procedure without sedation. Dietary and bowel preparation (with laxatives) are required beforehand. A flexible sigmoidoscopy is a shorter test to examine the distal part of the colon only.

An ERCP is an endoscopic test of the bile duct and, occasionally, the pancreatic duct. This is carried out by passing the endoscope through the mouth. This test is usually performed under intravenous sedation (with a benzodiazepine and opioid agent). The test is normally carried out to remove gallstone(s) in the main bile duct, or relieve bile duct obstruction (from gallstones or stricture).

This test combines the modality of endoscopy with ultrasound to obtain clear images of the internal organs in the chest and abdomen. Like ERCP, this is carried out by passing the endoscope through the mouth, under intravenous sedation. The procedure feels almost identical to the endoscopic procedure without the ultrasound part. The linear EUS enables safer ultrasound-guided biopsy of a lesion by using doppler function to avoid any adjacent blood vessels.

This is a type of endoscopy treatment whereby a stent (a tube made of plastic or flexible metal mesh) is inserted in a hollow organ or structure. An expandable metal stent can be inserted in the oesophagus, duodenum or bile duct for stricture due to an inoperable tumour.