Colorectal Cancer Screening

Colon cancer and rectal cancer can be prevented with screening. Screening can also detect colorectal cancer early, when it’s most curable.

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Colorectal Cancer Screening

The type of colorectal cancer screening you need will depend on your risk. If you have a higher risk of developing colorectal cancer, you should work with your doctor to create an individualized screening plan.

If you’re experiencing any signs of colorectal cancer, this may also influence your screening options.

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Why Get Screened?

If you have a colon (and you do!), talk to your doctor about colorectal cancer screening. It can save your life. While over 90% of colon and rectal cancers are found in people over age 50, anyone at any age can get CRC. All adults—starting at age 45 or before—should talk to their doctor about screening for polyps and cancer. Anyone experiencing signs and symptoms of CRC (at any age) should be screened. Screening should follow regular intervals through age 75, and people over that age should talk to their doctor about whether screening is necessary.

Colorectal Cancer Screening Options


Colonoscopy is often considered the “gold standard” for colon screening because it can identify polyps and remove them during the same procedure. 

What is a Colonoscopy?

A colonoscopy is a procedure where a colonoscope (a thin, flexible tube) is inserted into the colon and guided all the way through to the cecum (where the colon begins and the small bowel ends). To get to the colon, the colonoscope is inserted through the rectum.

The colonoscope has a digital camera and light attached to the end that allows doctors to see any abnormalities. This is why a colonoscopy is often referred to as a direct visualization test. 

During the procedure, the doctor will carefully examine the colon and rectum by looking for any growths or abnormalities. If any polyps are identified, the doctor can biopsy and remove them. Learn more about colonoscopy.

Colonoscopy Prep

To perform a colonoscopy, the entire colon must be cleaned out. This process is called colonoscopy prep, or simply “prep,” and involves taking a laxative and following dietary restrictions. Most often, patients are required to adhere to a clear liquid diet the day before the procedure. Read colonoscopy prep tips.

Colonoscopy Cost

The cost of a colonoscopy will depend on your insurance plan and coverage. If you’re considering skipping or postponing screening because you don’t have insurance or the funding, think again. There are ways to get a free or low-cost colonoscopy.

  • CDC’s CRCCP program: If you’re over age 45, check the Center for Disease Control and Prevention's Colorectal Cancer Control Program (CRCCP) to see if you’re eligible for free screening from a grantee near you.
  • Colonoscopy Assist: A colon cancer screening program designed to remove financial barriers to colorectal cancer screening for the uninsured.
  • Local Health Departments: Call your local health department and ask if there’s a state-funded program near you.
  • Primary Care Referrals: Ask your PCP if they know of a gastroenterologist who provides services to underinsured or uninsured. During March, Colorectal Cancer Awareness Month, many health care providers offer reduced-cost or free colonoscopies.

Stool Tests

Stool tests are typically done at home. Each comes with a set of instructions that are important to follow because each test is unique. For stool tests to work, you MUST do them regularly (annually or every three years, depending on the test). You will not have to touch the stool (but do a thorough hand washing once you’ve collected the sample).

Get a stool test for colorectal cancer from your health care provider. According to the NCCRT, stool-based tests are covered by the vast majority of insurers, including Medicare and many Medicaid plans. Both FIT and mt-sDNA tests must be ordered by a clinician, most commonly the patient’s primary care clinicians, although the tests can be ordered through urgent care centers, retail clinics, or independent telehealth providers.

Learn more about the NCCRT's efforts to maintain screening progress during the COVID-19 pandemic.

Cologuard (FIT-DNA/mt-sDNA)

A stool DNA test (like Cologuard ®) is an at-home test that looks for abnormal sections of DNA within the stool in addition to blood. You will be given instructions about how to use it the stool DNA kit at home, and where to send it when completed. One stool sample is needed. 


The gFOBT test is an in-home test used to detect blood in or on your bowel movements that can’t be seen by the naked eye. When you get a test, you will be given instructions about how to use it, which medications and foods to avoid (such as non-steroidal anti-inflammatory drugs and others), and where to send the completed test. Three stool samples are needed.

Test results of either “positive” or “negative” determine if bleeding is occurring; however, they don’t indicate the cause. If your test result is positive, talk to your doctor about getting a diagnostic colonoscopy to figure out the cause of the bleeding.

Fit Test (Fecal Immunochemical Test)

The FIT test works like the gFOBT test, however unlike the gFOBT, there are no drug or dietary restrictions. This test is also better at detecting blood than the gFOBT. One stool sample is needed. 

Virtual Colonoscopy

Virtual colonoscopy, also called CT colonography, is a non-invasive, advanced CT scan of the colon and rectum that produces two and three-dimensional images of the colon and rectum, allowing the doctor to look for polyps or cancer within the images.

The entire colon must be cleaned out for this procedure. If abnormalities are found, your doctor will talk to you about the appropriate diagnostic procedure moving forward.

Flexible Sigmoidoscopy

Prior to a flex sig, an enema is done to clean out the lower part of the colon and the rectum. A doctor then uses a sigmoidoscope to look at the sigmoid colon and the rectum, removing any visible polyps. Because less than half of the large intestine and all of the rectum can be seen with this method, they are often done in combination with the gFOBT or FIT test, to test for blood in the stool.

Blood-Based Tests


Simply stated: Blood-based screening tests are a less invasive screening test that use your blood sample to detect the presence of cancer and can be included in routine check-ups with your provider.

There are two different types of blood-based screening tests for cancer: Single-Organ screening tests and Multi-Cancer Early Detection (MCED) screening tests. So, what’s the difference?

Single-Organ Blood Screening Test:

  • These look at only one type of cancer.
  • A yearly sample needs to be taken.
  • If you receive a positive result, a follow-up colonoscopy is necessary.

Multi-Cancer Early Detection (MCED) Screening Tests:

  • Some can detect more than 50 types of cancers in one test.
  • These are designed to focus on tumors that are more aggressive.
  • They are used alongside single-organ tests for more accurate results.


Currently, only one blood screening test (Septin 9/Epi proColon®) is FDA approved for patients over 50 who avoid or are unable to undergo colonoscopy, FIT, or gFOBT screening tests; however, the research is accelerating quickly and soon there may be more options for blood-based screening tests. Manufacturers are working to ensure coverage of additional screening tests as they are approved by the FDA, but it is best to call your insurance provider to determine screening tests that are and are not covered.

Resource Highlight

Screening Brochure

If you’re age 45 or older, have a family history of colorectal cancer, or signs and symptoms, this Colorectal Cancer Screening brochure is for you. You need to be screened, but screening can be scary. Our screening brochure includes a colonoscopy prep shopping list and prep tips. We even outline alternative screening options in addition to colonoscopy. Our medically reviewed Colorectal Cancer Screening brochure is a resource you can depend on. Screening saves lives!

What are Polyps?

Colorectal cancers often take many years to grow, and most start off as a polyp. A polyp is a group of cells that grow together on the inside of the colon or rectum. Some polyps grow on the end of a stalk and look similar to a mushroom (this is called a pedunculated polyp), and some polyps, known as sessile or flat polyps, grow without the narrow stalk. Removing polyps can eliminate the chance they will turn into cancer. Not all polyps will become cancer, but it is important to remove them all to eliminate the possibility. Polyps can be detected and removed during a colonoscopy.

What if My Results Are Positive?

Not all positive tests mean you have polyps or cancer. If you had a positive stool test, CT colonography, or blood test, the next step is a colonoscopy to evaluate the positive result. This will be considered a diagnostic colonoscopy. If you have a colonoscopy and polyps are detected, your doctor will remove them and likely send them away for a biopsy.

If your biopsy results are positive for colorectal cancer, we're right here with you. Our community of relentless champions is here for you, too.

Preventive vs. Diagnostic -- What's the Difference?

Preventive screening is for patients within the screening age who are considered average risk. For this group, you have many options when it comes to getting your screening test done.

  • If you go for a routine screening and there is no need for a biopsy or polyp removal, this is called a preventive screening.
  • If you go for a routine screening and there is no need for a biopsy or polyp removal, this is called a preventive screening.
  • If you are in the office for a preventive screening and polyps are found, or a biopsy is needed, the test is still considered preventive screening.*

*If you are on Medicare this could have implications for cost. Medicare is in the process of phasing out costs for polyp removal but it is best to talk to your insurance company and your doctor about what this means for your colonoscopy and payment.

Diagnostic screening occurs when a patient is experiencing signs and symptoms of colorectal cancer. This can apply to anyone at any age.

Important Update: Effective May 31, 2022

Insurance plans must cover and may not impose cost sharing with respect to a colonoscopy conducted after a positive non-invasive stool-based screening test or direct visualization screening test.

High Risk for Colorectal Cancer Screening

If you or someone in your family has been diagnosed with a genetic syndrome (like Lynch syndrome) that increases the risk for colon or rectal cancer, it’s important to discuss colorectal cancer screening options with your doctor, as you may need to start screening earlier and get screened more frequently than the average-risk population.

It’s important to remember that rectal and colon cancer screening options may change over time as new technologies are developed and we learn more about genetic syndromes like Lynch and FAP. It’s important to talk with your doctor about appropriate screening tests and come up with the screening plan that works best for you.

To read about the screening recommendations for high-risk people with a genetic predisposition to colorectal cancer, download the Genetics Mini Magazine.

Removing Barriers to Screening

As an advocacy organization, we are relentlessly fighting to remove any and all barriers to colorectal cancer screenings. Learn more about our policy efforts that are pushing lawmakers to remove barriers to colorectal cancer screening.

Colorectal Cancer Screening Resources

Check out our screening resources in our Resource Library. We've got blog posts, webinars, podcasts, publications, and more.