What test is used to detect colorectal cancer?

The main test used to detect colorectal or colon cancer is the colonoscopy exam, according to the American Cancer Society. A colonoscopy is a procedure where a doctor carefully exams the entire length of the rectum and colon with a colonoscope, which is a device that is flexible, thin and has a camera attached to it.

Doctors can use other specific instruments that are fed through the colonoscope in order to biopsy or extract any suspicious material from the rectum or colon if necessary. Even though a colonoscopy is commonly done first to detect colon cancer, doctors may also order blood tests or perform a less complicated physical exam first, according to the American Cancer Society.