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Diagnosing Colorectal Cancer

At Dignity Health, we combine the latest diagnostic technology with the expertise of our physicians. Our goal is a precise and accurate diagnosis, so we can plan the most effective course of treatment.

Your doctor will begin the diagnosis by conducting a thorough physical exam and asking you about your symptoms and medical history. Be sure to be honest about what you are experiencing—your report of symptoms will help your doctor make the diagnosis.

Other tests and procedures your doctor may order:

Blood Test

There is no specific blood test to diagnose colorectal cancer. However, your doctor may order one to understand what is causing your symptoms and rule out other diseases.


During a colonoscopy, your doctor inserts a long, thin flexible tube into your rectum. A camera attached to the end of the colonoscope sends pictures to a monitor so your doctor can examine your colon and rectum. If your doctor sees any abnormalities, he or she can pass surgical instruments through the colonoscope and remove tissue samples (biopsy) to send to a lab for analysis.

Barium Enema

A barium enema combines a dye with an X-ray in order to get a detailed picture of your colon. The dye highlights any abnormalities so your doctor can see them clearly during the X-ray.

Computed Tomography (CT) Scans

A CT scan is a powerful X-ray that takes detailed images of your colon. Your doctor may order a virtual colonoscopy, which uses multiple CT images to get an accurate picture.