For many adults, colorectal cancer screening should begin at age 45. So when should you get a colonoscopy? That’s not a black and white answer since not everyone needs the same test on the same schedule. And although a colonoscopy is an important option, stool-based tests and other visual exams may also be appropriate for some people at average risk.
Your starting time for colorectal screening and follow-up plan depend on your age, health, prior test results, symptoms, and personal or family history. A conversation with your health care provider can turn a general guideline into a plan that fits you.
At What Age Should Colorectal Cancer Screening Begin?
Current guidance recommends that adults at average risk begin regular colorectal cancer screening at age 45.
For average-risk adults, screening generally continues through age 75. From ages 76 through 85, the decision is more individual. A provider considers overall health, life expectancy, prior screening, and personal preferences. The American Cancer Society’s 2026 guideline does not recommend continuing screening after age 85 or when life expectancy is less than 10 years.
These age ranges are starting points, not a substitute for personal advice. Someone with higher risk may need testing sooner or more often.
Who Needs a Colonoscopy Before Age 45?
Earlier or more frequent testing may be recommended for people at increased or high risk. Tell your provider if you have:
- A strong family history of colorectal cancer or certain colon polyps
- A personal history of colorectal cancer or certain polyps
- Inflammatory bowel disease, such as ulcerative colitis or Crohn’s disease
- A known inherited condition that raises colorectal cancer risk, such as Lynch syndrome or familial adenomatous polyposis
- A history of radiation treatment to the abdomen or pelvis for a prior cancer
Family-history recommendations depend on which relative was affected, the relative’s age at diagnosis, and what was found. Bring as much detail as you can to your appointment rather than guessing at your schedule.
Colonoscopy Screening and Diagnostic Colonoscopy Are Different
A screening test looks for disease before symptoms appear. A diagnostic colonoscopy helps investigate a symptom or an abnormal result. The procedure may be the same, but the reason for it is different.
Do not wait for a routine screening birthday if you develop concerning symptoms. A provider may recommend evaluation for:
- Blood in or on the stool
- A lasting change in bowel habits
- Diarrhea, constipation, or a feeling that the bowel does not empty fully
- Abdominal pain or cramping that does not go away
- Unexplained weight loss
- Iron-deficiency anemia without a clear cause
These symptoms do not always mean cancer. Hemorrhoids, medicines, infection, and other digestive conditions can cause similar problems. Still, the cause should be evaluated rather than assumed.
Is Colonoscopy the Only Screening Option?
No. Recommended screening choices for average-risk adults include stool-based tests and visual exams. Newer blood-based screening tests are also included in the American Cancer Society’s 2026 guidance, although the society does not list them as a preferred option because they are less likely to find precancerous growths and early-stage cancer.
Colonoscopy has a special role because a doctor can examine the entire colon, remove many polyps, and take a biopsy during the same procedure. It is like inspecting the inside of a pipe with a camera while also being able to remove a suspicious growth for testing.
Any positive result from a non-colonoscopy screening test should be followed by a timely colonoscopy. The best screening choice is one that is medically appropriate and that you can complete on schedule.
How Often Do You Need a Colonoscopy?
For an average-risk adult with a high-quality colonoscopy that is normal, the usual screening interval is 10 years. The next exam may be sooner when polyps are found, the bowel preparation was not adequate, the exam could not be completed, or personal risk changes.
Follow-up after polyps is based on the number, size, and type of polyps and on the quality of the exam. A diagnostic colonoscopy may also lead to a different follow-up plan. Use the written recommendation from the clinician who performed the procedure rather than applying the 10-year interval to every situation.
What Happens During a Colonoscopy?
A colonoscopy is performed by using a flexible tube with a small camera to look inside the rectum and colon. Sedation, anesthesia, or pain medicine is commonly given through an IV. During the exam, the doctor may remove polyps if they are present, or just take a small tissue sample for testing.
The preparation for a colonoscopy is essential because stool can hide the colon lining. Your care team will give specific instructions, which may include diet changes, clear liquids, and a laxative. Be sure to follow those instructions exactly as they are provided by your physician.
How Should You Prepare?
- Share your complete medicine and supplement list, including blood thinners, diabetes medicines, iron, and nonprescription products.
- Tell the team about kidney, heart, lung, bleeding, or other health conditions and about any prior difficulty with bowel preparation or anesthesia.
- Do not stop or change a medicine unless the prescribing clinician or procedure team tells you how to do so.
- Complete the full bowel preparation and call the team if side effects prevent you from finishing it.
- Arrange for a responsible adult to drive you home if you receive sedation or anesthesia.
What Are the Risks?
Colonoscopy is commonly performed, but no procedure is risk-free. Possible complications include bleeding, a tear in the colon wall called a perforation, and reactions to sedation or anesthesia. Risk can vary with age, health conditions, and whether a polyp is removed.
After the procedure, follow your discharge instructions. Seek medical care right away for severe abdominal pain, fever, bleeding that does not stop, bloody bowel movements that do not improve, dizziness, or weakness.
Questions to Ask Your Provider
- Am I at average risk or increased risk for colorectal cancer?
- Which screening options fit my health history and preferences?
- If I choose a non-colonoscopy test, what happens if the result is positive?
- When should I repeat screening based on my last result?
- How should I manage my medicines and health conditions during bowel preparation?
Key Takeaways
- Average-risk adults should begin regular colorectal cancer screening at age 45.
- Colonoscopy is one screening option; stool-based and other visual tests may also be appropriate for average-risk adults.
- Higher-risk patients may need testing before 45 or more often.
- Symptoms such as blood in the stool, lasting bowel changes, ongoing abdominal pain, unexplained weight loss, or iron-deficiency anemia need evaluation regardless of age.
- A normal, high-quality screening colonoscopy is often repeated in 10 years, but prior findings and personal risk can change the interval.
Conclusion
The right time for a colonoscopy is not determined by age alone. For many people, the first step is to begin screening at 45 and choose an appropriate test with a provider. For others, symptoms, family history, prior polyps, or another risk factor make an earlier or more specific plan important. If you are unsure whether you are due, ask a qualified health care provider to review your history and last screening result.
| “This article is intended for educational purposes only and should not be considered medical advice. Every patient and medical condition is unique. If you have questions about your health, symptoms, diagnosis, or treatment options, please schedule an appointment with a qualified healthcare provider. Information in this article is not a substitute for professional medical evaluation and care.” |
Sources Cited
American Cancer Society. Colorectal Cancer Screening Guideline. Updated 2026; accessed August 20, 2026. https://www.cancer.org/health-care-professionals/american-cancer-society-prevention-early-detection-guidelines/colorectal-cancer-screening-guidelines.html
National Institute of Diabetes and Digestive and Kidney Diseases. Colonoscopy. Last reviewed August 2023; accessed August 20, 2026. https://www.niddk.nih.gov/health-information/diagnostic-tests/colonoscopy
Centers for Disease Control and Prevention. Symptoms of Colorectal Cancer. Updated June 17, 2026; accessed August 20, 2026. https://www.cdc.gov/colorectal-cancer/symptoms/index.html