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How is colorectal cancer diagnosed?

If your doctor thinks you may have colorectal cancer, they will ask you questions about your medical history. You may also have a physical exam. Other tests may include:


In a colonoscopy (say "koh-luh-NAW-skuh-pee"), your doctor uses a lighted scope to view the inside of your entire colon. Polyps can be removed during this test. This test is recommended when another screening test shows that you may have colorectal cancer.


In a sigmoidoscopy (say "sig-moy-DAW-skuh-pee"), your doctor uses a lighted scope to view the lower part of your intestine. Doctors can also remove polyps during this test.

Barium Enema

A whitish liquid with barium is inserted through your rectum into your intestine. The barium outlines the inside of the colon so that it can be seen on an X-ray.


A sample of tissue is taken from the inside of your intestine and studied under a microscope. A doctor called a pathologist can look at the tissue sample and see if it contains cancer.

Complete Blood Count

This is a blood test. It is used to look for the cause of symptoms such as fatigue, weakness, anemia, bruising, or weight loss.


When you are diagnosed with colorectal cancer, your doctor may order other tests to find out if the cancer has spread.

© 2016-2021 Healthwise, Incorporated. This information does not replace the advice of a doctor.

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