Colonoscopy & Screening

When Is a Colonoscopy Needed?

Updated 2026-06-094 min read

Colonoscopy is used both to investigate symptoms and to screen for colorectal cancer in average and high-risk adults.

Symptom-based indications

Persistent change in bowel habit
Unexplained rectal bleeding
Iron-deficiency anaemia of unclear cause
Persistent abdominal pain or unintentional weight loss

Screening indications

Screening is generally considered from a defined age threshold for average-risk adults, and earlier in those with a family history of colorectal cancer or polyps. The clinician individualises the schedule.

What to expect

A clean bowel preparation is essential. The procedure is performed under sedation, allowing inspection of the colon and removal of polyps when needed.

This page is for general information only

The content here is not a diagnosis or treatment recommendation and does not replace an individual medical evaluation. If your symptoms persist, consult a physician. In emergencies call 112 or the nearest emergency department.

Symptoms Treatments FAQ

Frequently asked questions

Is colonoscopy painful?

It is performed under sedation, so most patients do not experience pain during the procedure.

How often should it be repeated?

The interval depends on findings and individual risk; the clinician will advise after the first study.