Several tests can screen for colorectal cancer. They differ in how they're done, how often they're needed, and what happens next. The best test is often the one you'll actually complete.
One key thing to know: if a non-colonoscopy screening test is abnormal, a colonoscopy is generally needed to complete the screening process — ideally within about six months.
A doctor uses a thin, flexible camera to examine the entire colon. Polyps can be found and removed during the same procedure, usually under sedation.
An at-home test that checks a stool sample for hidden blood, which can be an early sign of polyps or cancer. No prep, no sedation.
An at-home test that looks for both hidden blood and altered DNA/RNA markers shed by polyps or cancer cells in the stool. Examples include Cologuard Plus and ColoSense.
A CT scan creates detailed 3-D images of the colon to look for polyps and other changes. Bowel prep is still needed, but no sedation.
A blood test (such as the FDA-approved Shield test) that looks for tumor DNA signals in the bloodstream. Best considered a secondary option for people unwilling or unable to complete a preferred screening test.