Screening check
Colon cancer screening: when should I start?
For most adults, screening for colorectal cancer starts at 45. A family history or some health conditions can change that. Check where you stand in under a minute.
About you
Nothing you enter leaves this page.
What you will see
Whether average-risk screening applies to you at your age, or whether your history calls for a plan made with your doctor.
Educational only, not medical advice. Screening decisions are made with your doctor.
Source
US Preventive Services Task Force, 2021 recommendation. American Cancer Society colorectal cancer screening guideline.
Validated in
Adults at average risk with no symptoms. The higher-risk questions come from the American Cancer Society's definition of average risk.
Limits
Not for people with symptoms. Does not set a schedule for higher-risk people; that depends on details only your doctor can weigh.
When to start and when to stop
| Age | USPSTF 2021 | American Cancer Society |
|---|---|---|
| 45 to 49 | Screen (grade B) | Start regular screening at 45 |
| 50 to 75 | Screen all adults (grade A) | Keep screening |
| 76 to 85 | Offer selectively (grade C) | Decide based on preferences, life expectancy, health and past screening |
| Over 85 | Not covered by the recommendation | No longer screen |
Sources: USPSTF (USPSTF 2021), American Cancer Society (ACS).
The USPSTF lowered its start age from 50 to 45 in 2021 (USPSTF 2021). It estimates that 10.5% of new colorectal cancers occur in people younger than 50 (USPSTF 2021).
Which test, and how often?
The USPSTF does not rank the tests. Any of these counts as screening (USPSTF 2021):
| Test | How often | Where |
|---|---|---|
| FIT or high-sensitivity guaiac stool test | Every year | At home |
| Stool DNA-FIT | Every 1 to 3 years | At home |
| CT colonography | Every 5 years | Imaging center |
| Flexible sigmoidoscopy | Every 5 years, or every 10 years with a yearly FIT | Clinic |
| Colonoscopy | Every 10 years | Clinic or hospital, with sedation and bowel prep |
If you choose a test other than colonoscopy and the result is abnormal, it needs to be followed up with a timely colonoscopy (ACS). A home test is only a full screening plan if that follow-up happens.
When family history changes the plan
The age bands above are for people at average risk. The USPSTF recommendation does not apply to people with a previous colorectal cancer, adenomatous polyps, inflammatory bowel disease, or a known inherited syndrome such as Lynch syndrome or familial adenomatous polyposis (USPSTF 2021). The American Cancer Society also counts a family history of colorectal cancer and past radiation to the belly or pelvis as reasons someone is not at average risk (ACS).
For family history, the plan depends on who in the family had cancer and how old they were when it was found. Some people can follow the average-risk schedule; others need colonoscopy more often, possibly starting before 45 (ACS). Write down which relatives were affected and their age at diagnosis before you see your doctor.
Common questions
Why did the screening age drop to 45?
The USPSTF lowered it from 50 to 45 in 2021. It estimates that about 10.5% of new colorectal cancers occur in people under 50 (USPSTF 2021).
I am 40 and have blood in my stool. Should I wait until 45?
No. Screening ages are for people without symptoms. Bleeding, a lasting change in bowel habits or unexplained weight loss should be checked by a doctor at any age.
Do I need a colonoscopy, or is a home test enough?
Both are accepted screening options for people at average risk (USPSTF 2021). A home stool test has to be repeated on schedule, and an abnormal result needs a colonoscopy (ACS). Some higher-risk people need colonoscopy, and more often (ACS).
When can I stop?
The USPSTF recommends screening all adults through 75 and offering it selectively from 76 to 85 (USPSTF 2021). The American Cancer Society says people over 85 should no longer be screened (ACS).
Also see all screening tests by age, the lung cancer screening check, the breast cancer screening check, the cervical cancer screening check and the prostate cancer screening check.
Sources
- US Preventive Services Task Force. Screening for Colorectal Cancer: US Preventive Services Task Force Recommendation Statement. JAMA. 2021;325(19):1965-1977. www.uspreventiveservicestaskforce.org/uspstf/recommendation/colorectal-cancer-screening
- American Cancer Society. American Cancer Society Guideline for Colorectal Cancer Screening. www.cancer.org/cancer/types/colon-rectal-cancer/detection-diagnosis-staging/acs-recommendations.html
Written and maintained by the uncovermyrisk.com editorial team. We do not have a medical reviewer; every claim links to its primary source above. Last reviewed: 2026-10-29. Spotted an error? See About.