Colorectal Cancer

Stool Based Tests

These tests examine stool for markers of colorectal cancer such as blood. They are non-invasive, can be done at home, and require more frequent testing than visual exams.

Common types include: Fecal immunochemical test (FIT), Guaiac-based fecal occult blood test (gFOBT), and Multitargeted stool DNA/RNA tests.

Screening should begin at age 45, taper around 75, and stop by 85.

Test Type	Procedure	Screening Frequency
Fecal immunochemical test (FIT)	Checks for hidden blood in the stool and can be done at home; no dietary restrictions required.	Every year starting at age 45; a colonoscopy is needed if results are positive.
Guaiac-based fecal occult blood test (gFOBT)	Checks for hidden blood in stool less accurately than FIT; can be done at home; requires drug and diet restrictions.	Every year starting at age 45; a colonoscopy is needed if results are positive.
Multitargeted stool DNA/RNA tests	Screens for mutated sections of DNA/RNA in cancer cells plus blood; can be done at home; no drug/dietary restrictions. Popular option: Cologuard.	Every three years starting at age 45.

Colorectal cancer screening stool-based tests overview

Visual Exams

These exams look inside the colon and rectum for cancer or polyps. They are less frequent but more involved than stool tests.

Types include: Colonoscopy, CT colonography (virtual colonoscopy), Sigmoidoscopy.

Test Type	Procedure	Screening Frequency
Colonoscopy	Tube with light and camera inserted through the anus into the lower intestine; biopsies can be taken; special diet/fasting required; can be uncomfortable.	Every 10 years starting at age 45; genetic risk may need every 1-5 years.
CT colonography (virtual colonoscopy)	X-rays and CT scans take 3D pictures of the rectum/colon; no sedation; catheter placed into rectum; less invasive; special diet/fasting required.	Often every 5 years; follow clinician guidance.
Sigmoidoscopy	Scope examines the rectum and lower colon; prep required; quicker than a full colonoscopy.	Typically every 5 years for average risk; follow clinician guidance.