GI doctor’s thoughts on the Shield blood test for colorectal cancer screening
in Denver

In July 2024, the U.S. Food and Drug Administration (FDA) announced that it had approved Guardant Health’s blood test, called Shield, to screen for colorectal cancer.

At South Denver GI, we believe that this new screening option may encourage more people to be screened for colorectal cancer, which is critical. Colorectal cancer is the third leading cause of cancer death in the United States; however, it is a preventable and treatable cancer.

Shield works by detecting DNA that cancerous tumors release into the bloodstream. It is most effective in detecting later-stage cancers. Research shows that Shield is 83% effective in finding colorectal cancers. That means it misses 17% of colorectal cancers.

The Shield blood test is not a replacement for a colonoscopy. While the test can detect colorectal cancer, it cannot prevent cancer, like a colonoscopy can. Additionally, a positive Shield test requires a colonoscopy to determine if cancer is truly present or if the results were false.

Watch this video to hear Dr. Cary Patt’s thoughts on the blood test and its effectiveness as a colorectal cancer screening tool.

Read the American Gastroenterological Association’s 5 key takeaways from the FDA’s approval of the Shield blood test.