What is a colonoscopy?

A colonoscopy is a procedural examination of the inside of the large intestine, which includes the anus, rectum, and colon. This procedure utilizes an endoscope, or a flexible tube with a camera on one end, inserted into the body to provide the doctor with pictures of the large intestine.

A colonoscopy may be performed for diagnostic, preventive, or therapeutic means. One such use for a colonoscopy is for cancer screening of colorectal cancer. Since this type of cancer often has no symptoms, a colonoscopy screening is crucial for detecting it in its early stages.

The American Cancer Society recommends that adults undergo regular screening for cancer with a colonoscopy by the age of 45. Those with a family history of colorectal cancer may receive recommendations from their doctor to receive screenings even earlier or more frequently.

A colonoscopy may also be performed for diagnostic reasons for those with symptoms that include:

  • unexplained rectal discharge or bleeding
  • unexplained persistent abdominal pain
  • unexplained changes in bowel habits, such as constipation, diarrhea, or incontinence
  • unexplained weight loss


Why is a colonoscopy important in healthcare?

Colonoscopies can help diagnose the following diseases and conditions:

  • large bowel obstructions
  • intestinal ischemia and ischemic colitis
  • chronic colitis (e.g., Crohn’s disease or ulcerative colitis)
  • ulcers and perforations
  • diverticulitis and diverticulosis
  • colorectal polyps or cancer

For diagnostic purposes, the doctor performing the colonoscopy may take a biopsy while performing the colonoscopy.