The American Cancer Society's (ACS) recent update on colorectal cancer screening aims to strike a careful balance on blood-based screening tests. On the one hand, it appropriately calls them non-preferred options. On the other, it now includes them among acceptable screening choices for average-risk adults under limited circumstances.
That combination is likely to create more confusion than clarity. The document contains appropriate scientific caution, but insufficient implementation discipline. It recognizes the limitations of blood-based tests yet does not give clinicians or health systems the tools needed to prevent those tests from drifting into routine first line use.
The problem is not subtle. Once a screening test appears in a major guideline, patients, clinicians, health systems, payers, and the media often interpret that inclusion as endorsement. In practice, many will not distinguish between "listed as an option" and "recommended on equal footing." That is why it is not enough for a guideline to say blood-based tests are non-preferred. If those tests are added to the screening menu, there must also be a practical framework for implementation that makes their role unmistakable.
