diagnosis
What tests can diagnose colorectal cancer?
Doctors use several tests to check for colorectal cancer. One common test is a colonoscopy. It uses a thin tube with a light and a camera.
Doctors use a number of tests to find out whether someone has colorectal cancer.
These can include a physical exam, a digital rectal exam, a colonoscopy, stool tests, and a biopsy.
A colonoscopy uses a scope — a thin tube with a light and a tiny camera — to look at the whole colon and rectum. A flexible sigmoidoscopy is similar, but it checks only the rectum and the lower part of the colon. A virtual colonoscopy, also called CT colonography, is an X-ray test that looks inside the colon without using a scope.
A stool test checks a sample of stool for signs of blood. During a digital rectal exam, a doctor feels inside the rectum for anything unusual.
If a polyp — a small growth on the colon lining — is found during a colonoscopy, it can be removed and tested. Doctors may also take a small tissue sample, called a biopsy, along with other blood and tissue tests.
Screening tests look for signs of disease before symptoms appear, which can help find cancer early.
A care team can explain which combination of tests fits a person's situation.
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This page is educational, not medical advice. Talk with your care team about decisions that apply to you. If something feels urgent, contact your care team — for emergencies call your local emergency number.
More about Colorectal cancer
- Do I need colorectal cancer screening, and what does it involve?
- What does colorectal cancer staging mean, and why does it matter?
- What should I expect during a colonoscopy?
- What's the difference between a stool test and a colonoscopy for screening?
- How often do I need colorectal cancer screening?
- What can increase my risk of developing colorectal cancer?