Fecal immunochemical test (FIT): the pros, cons, and process
A fecal immune test (FIT) is an FDA-approved at-home colon cancer screening test that your doctor may recommend for you. Although colonoscopy is the gold standard, a FIT test is an option for some people.
The FIT test:
- Detects blood in the stool via antibodies
- Has no dietary restrictions
- Requires one bowel movement to test
- Is available over the counter does not require a prescription)
The details
The fecal immunochemical test (FIT), also called an immunochemical fecal occult blood test (iFOBT), is a stool test that also detects occult (hidden) blood in the stool. It is also known as a hemmocult test.
Detecting blood in the stool is important because it can be a sign of precancerous polyps or colorectal cancer. Blood vessels on the surface of larger polyps or cancers are often fragile and may be damaged by passing stool. The damaged blood vessels usually release a small amount of blood into the stool. This blood is often not visible to the naked eye, which is why these tests are helpful.
If a FIT test is positive, a colonoscopy will be needed to find the reason for the presence of blood. Although cancers and polyps can cause blood in the stool, there are other causes too. Ulcers, hemorrhoids, diverticulosis (tiny pouches that form at weak spots in the colon wall) or inflammatory bowel disease (colitis) may also cause blood in your stool.
Also, unlike some other screening tests (including colonoscopy), this one must be repeated every year.
You can purchase a FIT test over-the-counter, but you should talk to your doctor first to make sure you use the type of screening that is best for you.
The FIT test: step by step
Read any included instructions carefully once you receive your test. The typical steps are described below:
- Position sample collection paper across rim of toilet bowl
- Make bowel movement onto collection paper
- Use kit applicator to collect sample and insert in collection tube
- Insert specimen pouch into return envelope and seal
- Immediately send sample packet to testing address by mail
The pros
- Can be completed with one bowel movement
- No special changes to diets or medicines
- No prep liquids or pills
- Inexpensive
- Done in privacy of your home
The cons
- Patients may find test unpleasant to do
- Has a high false-positive rate
- Does not provide a visual exam of the colon and rectum
- May miss polyps or tumors that bleed in small amount or not at all
- Tests may result incorrectly in warm climates or with postal delays
- Must be repeated every year
- Follow-up colonoscopy after a positive test may not be covered by insurance
If you get positive results
A positive FIT test result can indicate that abnormal bleeding is occurring somewhere in the digestive tract. This blood loss could be due to a number of things besides cancer, so if the test finds blood, a colonoscopy will be needed to look for the source. Let your doctor know right away if you have a positive result.
Does screening really prevent colorectal cancer?
Screening can detect polyps in their early stages of growth. While most polyps are harmless, a small percentage can develop into cancer. If a doctor removes a polyp that had the potential to become cancerous if left to grow, then they may have prevented colorectal cancer.
Encouraging your loved ones to screen
About one in three eligible people have not had colorectal cancer screening.
While many people are aware of the benefits of getting screened, they may need a little encouragement from their family and friends to follow through. Learn how you can play a significant role in your loved one’s health by providing that support.
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