An endoscopy is a minimally invasive procedure involving the insertion of a long, flexible tube (endoscope) directly into the body to observe internal organs and tissue. An endoscope has a tiny video camera at the end of it that captures images and videos in great detail, which specialists such as Dr Ong use to aid diagnosis.

In the context of the gastrointestinal system, an endoscopy is a nonsurgical procedure used to examine changes in your digestive tract. In a gastrointestinal endoscopy, tissue/organ samples (biopsies) may also be obtained to aid diagnosis. There are generally three types of diagnostic gastrointestinal endoscopy:

1. Oesophago-Gastro-Duodenoscopy (OGD) – Also called upper gastrointestinal endoscopy or Gastroscopy, an OGD is an endoscopy whereby the endoscope is introduced into the body through the mouth and throat (upper gastrointestinal tract). This examines your oesophagus (gullet), stomach, and the first part of your small intestine (duodenum).

2. Colonoscopy – An endoscopy whereby the endoscope is introduced into the body through the anus and rectum (lower gastrointestinal tract). This examines your large intestine (colon and caecum) and may also examine the last part of the small intestine (ileum).

3. Capsule endoscopy – An endoscopy whereby a wireless camera small enough to fit into a capsule is swallowed by the patient. As the capsule travels through the digestive tract, it captures thousands of images and wirelessly transmits them to a hard disk worn as a belt by the patient. The capsule is later passed out together with stool.