Routine colon cancer screening offers options besides colonoscopy. Learn about at-home stool tests and how they help find cancer.

If your healthcare professional has recommended colon cancer screening, you may think you have only one option — a colonoscopy. But many tests can help detect signs of cancer. At-home stool tests are one example.

Screening tests are for people who aren't at a high risk of colorectal cancer and who don't have symptoms of colon or rectum cancer. These symptoms may include blood in the stool or in the toilet. Other symptoms include pain in your abdomen, a change in bowel habits, unexplained weight loss or a blood clot in the lung.

What is colon cancer screening?

A colon cancer screen is a test that checks for signs of cancer in the colon or rectum. This test can help your healthcare team find cancer early when it may be easier to treat. Colon or rectum cancer is commonly called colorectal cancer.

Colonoscopy is often recommended as a screening test. It allows healthcare professionals a way to see inside the colon and rectum and to remove lesions or polyps. But colonoscopy involves bowel preparation and sedation. It may be expensive. And it isn't an option you can do at home.

A more convenient option may be an at-home stool test.

How do stool tests find cancer?

At-home stool tests are simple, safe and accurate. You can take the test in the privacy of your home. There's little to no preparation, and you don't need to miss work.

There are two common types of stool test. One test checks for hidden blood in stool samples. The second test checks for DNA in stool samples.

What are the types of at-home stool tests?

A fecal occult blood test (FOBT) looks for tiny amounts of hidden blood in stool. Hidden blood can't be seen just by looking at the stool. The medical term for hidden blood is occult blood. Occult blood in the stool may be a sign of cancer or polyps in the colon or rectum.

Polyps are growths of cells that aren't cancerous but could become cancerous over time. Adenomas and serrated lesions are two types of polyps that could become cancerous.

There are two types of fecal occult blood tests: fecal immunochemical test (FIT) and guaiac fecal occult blood test (gFOBT). Fecal occult blood tests are proved to reduce deaths from colorectal cancer.

A multitarget stool DNA test (sDNA) looks for hidden blood and cells in stool. The cells are checked for DNA changes shed from polyps and cancer along the colon and rectum.

Fecal immunochemical test

A fecal immunochemical test (FIT) uses antibodies to find tiny amounts of hemoglobin in your stool. Hemoglobin is a protein in your blood. FIT looks for blood from the lower digestive tract but not from the upper digestive tract. This test is recommended every year.

How you take the test:

• You don't need to prepare for this test. You can eat, drink and take your medicines as usual before you collect a stool sample.
• The kit typically includes everything you need to complete the test, including instructions. The test kit may include a stick or brush that you use to collect the sample.
• You collect a stool sample from one bowel movement. After you collect the stool sample, place the sample in a container that comes with the test kit.
• Return the container to a lab for testing, often by mail. Send it within 24 hours.

Guaiac fecal occult blood test

A guaiac fecal occult blood test (gFOBT) uses antibodies to find tiny amounts of hemoglobin in your stool. The test can find bleeding from both the upper and lower digestive tract. This test is recommended every year.

How you take the test:

• Your healthcare professional may ask you to avoid certain foods, vitamins and medicines because they may affect the test results. Foods to avoid include red meat and fruits and vegetables that have vitamin C. Also avoid vitamins that contain vitamin C and iron. Medicines to avoid include aspirin, ibuprofen (Advil, Motrin IB and others) and blood thinners.
• The kit typically includes everything you need to complete the test, including instructions. The test kit may include a stick or brush that you use to collect the sample.
• You collect parts of three bowel movements in a row.
• You smear samples from each bowel movement onto a card provided in the test kit. You typically send the card to a lab for testing.
• After you collect the stool sample, place the sample in a container that comes with the test kit. Return the container to a lab for testing, often by mail. Send it within 24 hours.

Multitarget stool DNA test

A multitarget stool DNA test (mt-sDNA) finds tiny amounts of hemoglobin and cells in your stool. The test checks for changes in the cells' genetic material, which also is called DNA. Certain DNA changes are a sign that cancer is present or that it might happen in the future.

A stool DNA test (Cologuard) checks for bleeding from the lower digestive tract. This test is recommended every three years.

How you take the test:

• You don't need to prepare. You can eat, drink and take your medicines as usual before you collect a stool sample.
• This test is only available with a prescription. You receive the kit in the mail.
• The kit includes a container that attaches to the toilet. The kit also contains a preservative solution that you add to the stool sample before sealing the container.
• You collect one entire bowel movement in the container.
• After you collect the stool sample, return the sealed container to your healthcare professional's office or ship it to the lab. Return it within 24 hours.

What are the risks of at-home stool tests?

A stool test may lead to more testing. A stool test result is either negative or positive.

• If no blood or cancer DNA is found, the test result is negative. You don't need a follow-up test.
• If blood or DNA is found, the test result is positive. You need a follow-up test. The most common follow-up test is a colonoscopy. During this test, a healthcare professional may remove lesions or polyps while looking at the inside of the colon and rectum.

A stool test isn't always accurate. Sometimes, at-home stool tests can be wrong:

• A false-negative result means that the test says you don't have colorectal cancer or polyps when you may have either. A false-negative can happen if you have cancer or polyps that don't bleed. Or if there is blood or DNA changes that the test doesn't find.
• A false-positive result means that the test says you may have colorectal cancer or polyps when you really don't. A false-positive can happen if bleeding comes from another source such as a stomach ulcer or a hemorrhoid.

How do stool tests compare to each other?

• The stool DNA test finds colorectal cancer and advanced lesions better than the fecal immunochemical test and guaiac fecal occult blood test.
• The FIT finds cancer and polyps or advanced adenomas better than the gFOBT.
• The FIT has fewer false-positives than gFOBT and stool DNA test.
• The FIT and gFOBT usually cost less than the stool DNA test.
• The stool DNA test is recommended every three years. The FIT and gFOBT are recommended every year.

Does insurance pay for screening tests?

Insurance providers typically pay for colorectal cancer screening tests. Talk with your insurance provider to confirm what your plan covers.

Are stool tests only available by prescription?

Your healthcare professional may give you a fecal occult blood test kit or arrange to have the kit mailed to you. You may have an option to have the kit sent to your pharmacy for you to pick up.

Certain test kits are sold without a prescription. Some kits instruct you to send your sample to a lab. Other kits give the results in a few minutes. It's important to report your results to your healthcare professional.

Stool DNA kits are only available with a prescription. You receive the kit in the mail. You might also pick it up at the pharmacy where the prescription was sent, as you do with prescriptions for medicines.

The bottom line

Colon cancer screening tests — including at-home stool tests — save lives. Colonoscopy is more accurate than at-home stool tests at finding cancer, advanced adenomas and serrated lesions. Yet, at-home stool tests are a simple, effective way to help catch cancer early.

Talk with your healthcare professional about your options for colorectal cancer screening. The test that's right for you is the test that you complete.

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Oct. 30, 2025 See more In-depth