Key takeaways:
There are three types of at-home, stool-based tests for colon cancer screening.
These tests are more convenient than a colonoscopy. But they need to be done more often, and they aren’t as accurate.
At-home tests are best for adults ages 45 to 75 with average risk. They aren’t recommended for people at higher risk for colorectal cancer.
Experts recommend colon cancer screening for most adults starting at age 45. The goal of screening is to find early cancers or precancerous polyps (growths in the colon) that can become cancerous over time. Screening for colon cancer can be life-saving. That’s because colon cancer treatment works best the earlier it’s found.
When most people think of colon or rectal cancer screening, they think of a colonoscopy (a camera test that looks at the inside of the large intestine, or colon). While a colonoscopy is the most accurate screening tool, it’s not the only test out there. In fact, you can perform your own colorectal screening test in the comfort of your own home.
We’re here to help you understand how accurate and reliable these at-home tests are and when it’s best to visit a healthcare professional instead.
How do at-home colon cancer tests work?
The FDA has approved three types of at-home tests for colon cancer. They require a sample of your stool (feces or poop). You send the samples to a lab and wait for the results.
Two types of tests work by looking for blood in the stool. This is because most cancers bleed into the colon or rectum. You may not be able to see the blood, but colon cancer tests can detect it. This is called occult blood. The other type of test looks for cancer DNA or RNA in the stool.
Guaiac fecal occult blood test
Guaiac fecal occult blood test (gFOBT) uses a chemical called guaiac to look for occult blood in the stool.
To do the test, you collect stool samples from three separate bowel movements. You use a stick or swab to take a small sample of stool and apply it to a test card. Your kit will come with instructions and the materials you need to collect your samples.
Certain medications (like nonsteroidal anti-inflammatory drugs or NSAIDs), vitamin C supplements, and some foods can affect the test results. So it’s best to avoid them before your test.
Fecal immunochemical test
Like gFOBT, the fecal immunochemical test (FIT) detects blood in the stool. The difference is that it uses antibodies (instead of guaiac).
FIT is used more often than gFOBT because it’s easier to do. You only need to collect one sample, and you don’t need to stop any foods or medications before the test. FIT is also more likely to give accurate results than gFOBT.
Stool DNA and RNA tests
These tests check the stool for DNA or RNA from cancerous or precancerous cells in the colon, as well as blood (FIT, as above). Examples include Cologuard (DNA) and ColoSense (RNA).
To do the test, you’ll need to collect a whole stool sample for the test (compared to the small sample needed for gFOBT and FIT). You don’t have to change your diet or stop any medications before doing the test.
How do you get the results?
Follow the specific instructions in your kit on how to collect the sample and send it back for testing. The kit will have information about how you’ll get the results. If your healthcare team ordered the test, they’ll get the results and then share them with you.
If an at-home colon cancer test is positive, the next step should be a colonoscopy to look for the cause of the bleeding. Your healthcare team can help you understand your results and discuss next steps with you.
How do at-home stool tests compare to each other?
Studies suggest that FIT is more sensitive than gFOBT. In other words, FIT is more likely to detect cancer than gFOBT. But gFOBT is still better than no screening at all.
DNA plus FIT testing is also more sensitive for detecting cancer, but it still may miss some early, precancerous lesions. RNA testing was approved in 2024, so there isn’t much comparative data available. But studies suggest it’s as sensitive as DNA testing for detecting cancer, and it may be more sensitive for picking up early lesions.
It’s important to note that any positive result — regardless of the type of stool test — should be followed up with a colonoscopy.
In addition to the differences in sensitivity, there’s also a difference in how often these tests should be performed.
How often should you check for colon cancer with an at-home test?
How often you screen for colon cancer depends on which at-home test you use. If you have an average risk for colon cancer, here’s the recommended timing by test:
FIT: every year
gFOBT: every year
Stool DNA testing: every 3 years
For comparison, a colonoscopy should be done every 10 years (if the results are normal and you don’t have other risk factors).
Who should use at-home colon cancer tests?
At-home screening tests are best for people with an average risk of colon cancer. This means you don’t have risk factors for colon cancer other than age.
Who shouldn’t use at-home colon cancer tests?
People with higher risk of colorectal cancer should opt for a colonoscopy as a screening test, rather than an at-home stool test. You have a higher risk for colorectal cancer if you have any of the following:
A history of colon cancer or polyps
A family history of colon cancer or polyps
Inflammatory bowel disease (like Crohn’s disease and ulcerative colitis)
A personal or family history of a high-risk condition, such as Lynch syndrome or familial adenomatous polyposis
If you’re not sure, your healthcare team can help you decide on the best way and time to screen for colon cancer.
What are the benefits and risks of at-home colon cancer tests?
Like with most things, it’s important to weigh the benefits versus the risks of at-home colon cancer tests.
Benefits of at-home colon cancer tests
If you have average risk for colon cancer, at-home tests have a few benefits that may make them a good option for you:
Convenience: You can do at-home tests at any time. Test kits for each type of home stool-based test will give you the supplies and instructions you need.
No appointments: Compared to a colonoscopy, you don’t need to take time off from work or arrange transportation.
No bowel prep or sedation: There’s no need for bowel prep (emptying your bowel ahead of time), and the tests don’t require sedation like a colonoscopy.
Lower cost: At-home tests are typically cheaper than the cost of a colonoscopy.
Risks of at-home colon cancer tests
At-home colon cancer screening also comes with some downsides:
Accuracy: All at-home tests detect fewer cancers than colonoscopy. They also have the potential for false positive results. This is when the test suggests you have colon cancer when you really don’t.
Utility: A colon cancer screening test is only useful if a lab can process the sample. A large study found that more than 1 in 10 samples of FIT tests couldn’t be processed by a lab. The most common reasons for this were people not sending enough stool sample, waiting too long to send, or incorrectly labeling them.
Frequency: At-home stool tests need to be done much more frequently than a colonoscopy.
Discomfort: Some people may not be comfortable handling stool samples. And you run the risk of finding out that you didn’t provide an adequate sample for testing, in which case you’ll need to provide another sample.
Can you buy colon cancer tests over the counter?
You can buy some colon cancer screening tests over the counter at your local pharmacy or online. You’ll need a prescription from a healthcare professional for stool-based DNA tests. But you can buy some gFOBT and FIT tests without a prescription.
To make sure you get the best test, your healthcare team can often give you a test kit at your appointment or help you find a test that’s right for you.
How accurate and reliable are at-home colon cancer tests?
While colonoscopy is the best test for colon cancer screening, at-home colon cancer tests are also accurate. FIT is better at accurately detecting colon cancer compared to gFOBT. For this reason, FIT is often preferred over gFOBT. That said, both FIT and gFOBT have been shown to lower the number of deaths from colon cancer.
Stool DNA tests can give positive results that aren’t really positive. The downside of this is it can lead to more colonoscopies being done for tests that aren’t actually abnormal.
Are at-home colon cancer tests a good alternative to a colonoscopy?
Colonoscopy has a 100% detection rate for colon cancer. A physician performs a colonoscopy using a long, thin instrument with a camera on the end. This lets them see inside the colon and remove any polyps.
So how do at-home screening tests compare? They aren’t as sensitive. But they can be a good alternative to colonoscopy for people at average risk of colon cancer and who can’t or won’t get a colonoscopy. Doing an at-home test is much better than not screening for colon cancer at all. For people with a higher risk of colon cancer, a colonoscopy is the best screening test.
When to see a doctor for colon cancer screening
At-home colon cancer tests are only used for screening. They don’t diagnose colon cancer. If you have symptoms that could be from colon cancer, talk with a healthcare professional before doing any testing.
Colon cancer symptoms can include:
Weight loss
Abdominal pain
A change in bowel habits
These symptoms can be from colon cancer, but there are also other causes. Your healthcare team can make sure you get the right testing to figure out the correct diagnosis.
Frequently asked questions
Colorectal cancer screening is preventive, and it’s part of required coverage for health plans. Your insurance plan might not cover every type of screening option, so you should check to be sure. At-home screening tests are usually covered by Medicare, Medicare Advantage, and Medicaid, as well as some private insurance plans.
If you don’t have health insurance, there may be some free screening programs available in your community.
The 3-2-1 rule was previously used to help diagnose Lynch syndrome, or hereditary non-polyposis colorectal cancer (HNPCC). People with this condition are at higher risk of colon cancer. The criteria are as follows:
Three family members with verified colorectal cancer
At least two generations affected
One colorectal cancer occurring before age 50
Better testing is now available to identify hereditary syndromes that can cause colorectal cancers.
Colorectal cancer screening is preventive, and it’s part of required coverage for health plans. Your insurance plan might not cover every type of screening option, so you should check to be sure. At-home screening tests are usually covered by Medicare, Medicare Advantage, and Medicaid, as well as some private insurance plans.
If you don’t have health insurance, there may be some free screening programs available in your community.
The 3-2-1 rule was previously used to help diagnose Lynch syndrome, or hereditary non-polyposis colorectal cancer (HNPCC). People with this condition are at higher risk of colon cancer. The criteria are as follows:
Three family members with verified colorectal cancer
At least two generations affected
One colorectal cancer occurring before age 50
Better testing is now available to identify hereditary syndromes that can cause colorectal cancers.
The bottom line
At-home, stool-based colon cancer tests are a convenient way for people with an average risk to screen for colon cancer. They aren’t as sensitive as colonoscopy and must be repeated more frequently. Screening for colon cancer can help detect cancer earlier, making treatment more effective. There are different ways to do it, but the best type of screening is the one you and a healthcare professional decide is right for you.
Why trust our experts?
References
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Barnell, E. K., et al. (2023). Multitarget stool RNA test for colorectal cancer screening. JAMA.
Centers for Disease Control and Prevention. (2026). About Lynch syndrome.
Imperiale, T. F., et al. (2024). Fecal DNA versus fecal occult blood for colorectal-cancer screening in an average-risk population. The New England Journal of Medicine.
Liu, P., et al. (2023). Unsatisfactory fecal immunochemical tests for colorectal cancer screening: Prevalence, reasons, and subsequent testing. Cancer Epidemiology, Biomarkers and Prevention.
MedlinePlus. (2025). Familial adenomatous polyposis.
Muller, C., et al. (2019). Effective identification of Lynch syndrome in gastroenterology practice. Current Treatment Options in Gastroenterology.
National Cancer Institute. (2024). Screening tests to detect colorectal cancer and polyps. National Institutes of Health.
National Human Genome Research Institute. (2026). Antibody.
National Human Genome Research Institute. (2026). Deoxyribonucleic acid (DNA).
National Human Genome Research Institute. (2026). Ribonucleic acid (RNA).
Robertson, D.J., et al. (2017). Recommendations on fecal immunochemical testing to screen for colorectal neoplasia: A consensus statement by the US Multi-Society Task Force on Colorectal Cancer. Gastroenterology.
Shaukat, A., et al. (2021). ACG clinical guidelines: Colorectal cancer screening 2021. The American Journal of Gastroenterology.
U.S. Preventive Services Task Force. (2021). Screening for colorectal cancer: US Preventive Services Task Force recommendation statement. JAMA.
