Camera test
Colonoscopy
A colonoscopy uses a thin, flexible camera to examine the inside of the large bowel. It can find and remove growths (polyps) and is key in investigating bowel symptoms and bowel cancer screening.
Quick answer
Colonoscopy: what it is and what the results mean
A colonoscopy passes a flexible tube with a camera through the back passage to view the whole large bowel (colon).
- Why it is done: It investigates symptoms such as bleeding, changes in bowel habit, or abdominal pain, follows up abnormal screening results, and can remove polyps before they become cancer.
- Understanding results: The doctor usually sees the bowel lining directly and can remove polyps or take biopsies during the test; sample results follow later.
What it is
A colonoscopy passes a flexible tube with a camera through the back passage to view the whole large bowel (colon).
Why it is done
It investigates symptoms such as bleeding, changes in bowel habit, or abdominal pain, follows up abnormal screening results, and can remove polyps before they become cancer.
What to expect
You take a strong laxative preparation beforehand to empty the bowel — this is the least pleasant part. During the test, done with sedation or gas-and-air, the camera is passed while you lie on your side; it takes 30–45 minutes.
Understanding the results
The doctor usually sees the bowel lining directly and can remove polyps or take biopsies during the test; sample results follow later. Findings guide any treatment or follow-up.
Good to know
Risks and limitations
Colonoscopy is generally safe, though there are small risks including bleeding or, rarely, a tear in the bowel. With sedation you will need someone to take you home.
Education and reference only. This explains the test in general terms and is not medical advice. Always follow the specific instructions from the team arranging your test, and discuss your results with your clinician.
Answers
Colonoscopy: frequently asked questions
Why do I need bowel prep before a colonoscopy?
The bowel must be completely empty for a clear view, so you take a laxative preparation beforehand. It is the least pleasant part but essential for an accurate test.
Does a colonoscopy hurt?
It can cause some cramping or bloating, but sedation or gas-and-air is offered to keep you comfortable. Most people tolerate it well.
Related tests
Other camera test investigations
Sources
Where this is drawn from
- NHS — Tests and treatments
- NICE — diagnostic guidance
- Royal College of Radiologists / relevant professional body
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