What is a colonoscopy? When should I get one? Should everyone get one?


Written by: Dr. Husam Alnaadi


A colonoscopy is a medical examination done to evaluate the condition of the digestive system. This test evaluates the lower part of the digestive system (the colon), using a flexible plastic tube attached to a small camera (optic fiber). The tube is inserted into the rectum and photographs the colon, up until where it connects to the small intestine.



In addition to the photographs, the physician can take a biopsy for laboratory tests in order to ensure that the patient gets the most accurate diagnosis. A colonoscopy can also be used to remove polyps from the colon.


Preparing for a colonoscopy requires fasting and drinking liters of bowel irrigation fluid (or laxatives). This empties the colon of stool residue. A colonoscopy can be used to check the entire colon or only the lower area (sigmoidoscopy).


A colonoscopy is performed under anesthesia, usually in a day-care unit. It is important to come with an accompanying person. A colonoscopy will be ordered by a gastroenterologist.


When Should I Have a Colonoscopy?

  • Used for early detection of polyps and growths in the colon
  • Monitoring polyps that were previously detected, or monitoring past diseases
  • An evaluation for patients who tested positive for blood in stool
  • An evaluation for patients who have symptoms that include changes in stool, anemia or rectal bleeding
  • Diagnosis/monitoring of IBDs
  • Evaluation prior to performing a surgery of the colon
  • Recommended for people age 50+ for early detection of colon cancer