Patient education: Fecal immunochemical test (The Basics)

What is a fecal immunochemical test? — A fecal immunochemical test, or "FIT," is a type of lab test done on a stool sample. "Fecal" means related to stool or bowel movements.

The test looks for blood in the stool. It can find even tiny amounts of blood that cannot be seen. It can show if there is bleeding in the colon or rectum (figure 1).

For a FIT, you collect a sample of stool and send it to a lab for testing.

Why might I get a FIT? — The main reason is to "screen" for colon and rectal cancer.

Screening is a way that doctors check the colon and rectum for signs of cancer or "polyps." Polyps are growths that might become cancer. Cancers and polyps can bleed. This can show up on the test, even if there is only a small amount.

When a FIT is used for cancer screening in the US, it is usually repeated every year.

How do I prepare for a FIT? — You should not need to do anything special to prepare.

Your doctor will give you a kit to use to collect a stool sample at home. In some cases, they might have you get the kit from a pharmacy or by mail.

Ask your doctor or nurse if you have any questions about how to prepare for the test.

How do I collect a stool sample? — Each test kit comes with specific instructions. Read and follow the instructions carefully.

In general, these are the steps:

●Prepare your kit when you are ready to have a bowel movement.

●Place the paper from the kit in the toilet, on top of the water. Your bowel movement will land on the paper.

●Use the tool in the kit to get a small sample of your stool. The tool might look like a small brush or stick.

●Put the sample in the container or bag that comes in the kit. Make sure that your name and any other required information is on the container.

●Flush the toilet. The paper can be flushed.

●Wash your hands.

●Follow your doctor's instructions for when and how to return your sample. They might want you to bring it in or mail it to the lab.

What do my results mean? — Your doctor or nurse will tell you when to expect your results, and will contact you with the results. Or if you use an online "patient portal," you might get an alert there when your results are ready.

The result can be:

●Negative – This means it did not find blood in your stool sample.

●Positive – This means it did find blood in your stool sample. Your doctor or nurse will talk to you about what to do next. In most cases, they will want to do another test called a "colonoscopy" to learn more about the cause of the bleeding. For a colonoscopy, a doctor puts a thin tube into your anus. Then, they gently move the tube up into your rectum and colon to check for polyps or signs of cancer.

If you do have a health problem, your doctor will work with you to come up with a plan for treatment.

More on this topic

Patient education: Colon and rectal cancer screening (The Basics)
Patient education: Colon and rectal cancer (The Basics)
Patient education: Colon polyps (The Basics)
Patient education: Colonoscopy (The Basics)

Patient education: Screening for colorectal cancer (Beyond the Basics)
Patient education: Colon and rectal cancer (Beyond the Basics)
Patient education: Colon polyps (Beyond the Basics)
Patient education: Colonoscopy (Beyond the Basics)