Question 225 of 433
Colonoscopy, stool test, or blood test: which is best for colon cancer?
The short answer
Colonoscopy is the most thorough because it finds and removes polyps before they become cancer. The best test, though, is the one you will actually do.
Colonoscopy every ten years if normal. It both detects and prevents.
A yearly stool blood test (FIT) is inexpensive and done at home.
A stool DNA test every three years finds more than 90 percent of cancers and many advanced polyps.
A blood test for colon cancer was approved in 2024. It detects about 83 percent of cancers but only a small share of precancerous polyps, so it catches cancer and does little to prevent it. It is better than no screening and not as good as the others.
Any positive stool or blood test must be followed by a colonoscopy.
Colon cancer is rising in adults under 50. At any age, do not ignore rectal bleeding, a lasting change in bowel habits, unexplained iron-deficiency anemia, or unexplained weight loss.
“This book is for education. It is not medical advice, and reading it does not make you my patient or create a doctor-patient relationship.” From the book’s medical disclaimer. Full disclaimer
HUMAN STUDIES / GUIDELINE — Average-risk colorectal screening: detection and prevention differ by test; positive noninvasive tests need colonoscopy.Evidence grade (draft mapping)GGuideline-based / consensusPart 16, Q225 · Part sources
From Longevity Unmasked by Afshine Ash Emrani, MD, FACC. Medical disclaimer. This book is for education. It is not medical advice, and reading it does not make you my patient or create a doctor-patient relationship. Nothing here is meant to diagnose, treat, cure, or prevent any disease. Medicine is personal: a test, drug, supplement, or exercise plan that helps one person can harm another. Do not start, stop, or change any medication or treatment because of something you read in these pages. Talk with a licensed clinician who knows your history first. If you think you are having a medical emergency, call 911. The author disclaims responsibility for any loss or harm arising from use of the information in this book.