There are many screening methods that can detect precancerous polyps:

  • Colonoscopy
  • Flexible sigmoidoscopy
  • CT colonography (virtual colonoscopy)
  • Stool DNA test (Cologuard®)
  • Fecal immunochemical test (FIT)
  • High-sensitivity guaiac fecal occult blood testing (FOBT)

All methods can detect polyps and cancers to varying degrees. The benefits of some of the stool-based tests are that they are noninvasive tests and can be performed at home. But they must be done more frequently (every one to three years) to detect colorectal cancers. They are less sensitive in detecting polyps than colonoscopy.

The blood test, Shield®, is FDA approved but has a low polyp detection rate.

The more invasive, direct visualization techniques (colonoscopy, CT colonography, flexible sigmoidoscopy) allow doctors to see polyps. These screening tests can be done less frequently. Colonoscopy and flexible sigmoidoscopy allow for the identification and removal of polyps.