Colonoscopy vs. Cologuard®: what you need to know

Understand the benefits offered by both screening methods

In recent years, the Cologuard® colon cancer test has gained increased public visibility as an option for colon cancer testing. Cologuard offers a relatively convenient way to be screened by providing individuals with materials to collect a stool sample from home to send to a lab for testing. While it provides alternative option to a traditional colonoscopy, it’s important to know the extent of its effectiveness and what type of patient it serves best.

Differences in approach

Cologuard screens for colon cancer in a much different way than a colonoscopy does. With Cologuard, DNA from a stool sample is tested for the presence of occult blood and abnormal cancerous or precancerous cells, with no visual examination of the colon.

In contrast, with a colonoscopy, a gastroenterologist uses an endoscope to carefully examine the colon for polyps or cancerous lesions. If polyps are seen, they are removed. If any evidence of cancer is seen, a biopsy can be performed. Both resected polyps and tissue from potentially cancerous lesions are sent to a pathologist for microscopic examination.

As a result of its more thorough approach, colonoscopies can detect about 95% of all colorectal cancers and advanced precancerous polyps. While studies have shown that Cologuard can detect 92% of colorectal cancers, they also show that Cologuard can detect only 42% of precancerous polyps—making it a much less effective overall exam than a colonoscopy.

Low-risk individuals

If you have never had colon polyps, a colonoscopy beginning at age 50 (age 45 for African Americans) continues to be the gold standard screening recommended by gastroenterologists. Not only is a colonoscopy the only test that can prevent colon cancer, it also enables physicians to detect and remove precancerous polyps all in one exam. However, the Cologuard screening is a viable option for patients whose personal or family history indicates a low level of risk.

Individuals with family history of colon polyps/cancer

If you have a family member who has had colon polyps or cancer of any kind, a colonoscopy is the only test recommended for colon cancer screening. In fact, depending on factors in your family history, your physician may recommend a colonoscopy beginning at age 40 or possibly earlier. A screening via Cologuard is not recommended for patients who fall within this category.

Individuals with personal history of colon polyps/cancer

For patients who have had colon polyps or cancer, colonoscopy screenings will be a critical part of follow-up care. Your physician will recommend how often you should have a colonoscopy based on the number and size of precancerous polyps, types of polyps, how polyps were removed, and other factors. Again, Cologuard is not recommended as a component of ongoing polyp follow-up care.


Cologuard screening offers advantages over a colonoscopy in convenience and privacy; however, it should only be an option for individuals with no family history of colon polyps. Additional clinical studies of Cologuard have shown that 13% of people without cancer or precancerous polyps who were screened by this method tested positive, so there is a margin of error you will need to consider.

While a colonoscopy requires some pre-exam bowel preparation in addition to an appointment with a gastroenterologist, it is far more comprehensive in finding and treating precancerous conditions among a wide range of individuals. It is still considered by GI doctors and professional gastroenterology associations nationwide to be the gold standard procedure for preventing colon cancer. In all cases, be sure to consult your physician to determine the screening option that works best for you.

If you elect to use the Cologuard test as your preventative screening—and the results come back positive for possible colon cancer—your insurance will not cover your colonoscopy under your screening benefit for a follow-up colonoscopy that will be needed to confirm the result and/or to begin treatment. The only way to ensure greater peace-of-mind and take full advantage of your insurance plan’s preventative screening benefit is by having a colonoscopy as your initial screening.

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