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Screening and Testing

According to the Centers for Disease Control and Prevention (CDC), screening is when a test is used to look for a disease before there are any symptoms. Cancer screening tests, including those for colorectal cancer, are effective when they can detect disease early. Detecting disease early can lead to more effective treatment. In some cases, screening tests can detect abnormalities, such as polyps, before they have a chance to turn into cancer. Removing polyps in the colon and rectum prevents colorectal cancer from developing. If caught early, up to 91% of colorectal cancer (CRC) patients survive.

Screening Types

The U.S. Preventive Services Task Force (USPSTF) recommends:

  • an annual high-sensitivity guaiac fecal occult blood test (gFOBT), or fecal immunochemical test (FIT/iFOBT);
  • a sigmoidoscopy every five years, with FOBT every three years; or
  • a colonoscopy every 10 years.

Fecal Immunochemical Test (FIT)

Done once a year, the FIT is a newer kind of test that detects hidden blood only in the lower bowel. This test reacts to part of the human hemoglobin protein, which is found in red blood cells. This accurate test has very few false positives, resulting in fewer unnecessary colonoscopies.

The FIT is an easy way to be tested for colorectal cancer because:

  • it is done privately at home;
  • there is no need to change eating habits;
  • there is no need to change medications;
  • there are no liquids to drink;
  • there is no need to take time off from work; and
  • it is mailed back to the doctor in a few days.

The FIT or iFOBT is a take-home test that may be right for those who experience one or more of the following barriers to colonoscopy:

  • time;
  • transportation;
  • lack of health insurance;
  • lack of willingness to be screened; and/or
  • limited availability.

The Permanente Medical Group of Kaiser Permanente provides educational videos on the importance of colorectal screening and how fecal immunochemical tests are used.

Positive Test Results

If test results are positive, a colonoscopy is needed to see if there is cancer, a polyp, or other causes of bleeding. When colorectal cancer is found and treated early, it can be cured. When polyps are found and removed, colorectal cancer is prevented.

Please visit National Cancer Institute for a detailed description of colorectal cancer terms, risk factors, screening methods, and more.

Page last updated: May 13, 2021