Fecal Immunochemical Test (FIT)

This Test Can Detect Hidden Blood In The Stool

Toilet
When you are taking a FIT, you should flush the toilet before you move your bowels. This helps to get a clean sample for the test. Image © Peter Dazeley / Photographer's Choice / Getty Images

What Is An FIT Test?

A fecal immunochemical test (FIT) (also called an immunochemical fecal occult blood test or iFOBT) is used to test the stool for blood that can not be seen with the naked eye (called occult blood). An FIT is often used to detect bleeding in the digestive tract when there are no other signs or symptoms of a digestive problem. Blood in the stool can be caused by a number of conditions, including cancers of the digestive tract such as colon cancer.

If your doctor ordered this test, follow the instructions that were given. The good news is that it's a really easy test to do, it doesn't require that you prepare in any way. Try not to worry about why your doctor ordered the test: see what the results are first, and what your doctor thinks is going on before you start to think the worst.

How Is A Fit Different Than an FOBT?

An FIT is similar to a fecal occult blood test (FOBT), except that the FIT doesn't require patients to follow a restricted diet before taking the test. (To take an FOBT, patients must not eat any red meat and also must stop taking certain medications for a number of days prior to the test.) An FIT may not be able to detect blood from further up the digestive tract, such as in the stomach. This means that it is really more specific to finding blood coming from the lower gastrointestinal tract than the FOBT. Many patients also find the collection methods of the FIT easier than those of the FOBT.

Why FIT Is Used

Fecal occult blood tests such as the FIT or the FOBT are usually recommended at regular intervals to screen for colon cancer in people who are over the age of 50 years. People at high risk for colon cancer because of family history or polyps may begin testing earlier, as determined by a physician.

What's The Preparation For an FIT?

The FIT doesn't require any special preparation, but there are some conditions that could affect the results. You should not use the FIT if you:

  • Have active bleeding from hemorrhoid or anal fissure
  • Have blood in your urine
  • Are a woman having your menstrual period or during the three days after the end of your period

Toilet cleaners may affect test results and should be removed before using the FIT.

How A Fit Is Done

You will be given a kit to be used for collecting stool samples for the test. This kit should be kept in the bathroom at home, or carried with you when you're away from home during the test. Be sure to write your name and other information on the collection cards.

Flush the toilet before a bowel movement. After having a bowel movement, don't flush right away! Instead, brush the surface of the stool with one of the brushes from the kit for several seconds. Shake the brush once to dislodge any clumps of stool or excess water. Apply the sample by swabbing the appropriate spot on the test card for several seconds with the bristles of the brush.

Dispose of the brush as directed by the instructions included with the kit.

Repeat the process for one more bowel movement or as directed by your doctor. Cover the test cards and store them away from heat, light, and strong chemicals.

After finishing the test, seal the test envelope and return the kit to your doctor or the laboratory.

What Are The Risks?

This test is safe and painless.

Following Up After The Test

Call your doctor in a few days for the results. If the test shows that there is blood in the stool (a positive test) -- don't panic! There are many reasons that blood could be in the stool. Your doctor will likely want to do more tests to find out why the blood is there. In some cases, another test called a colonoscopy may be recommended.

If the test is negative (and shows no blood in the stool), find out what your doctor wants you to do next (if anything) and if the test should be repeated after a period of time (such as 1 year or 5 years).

Call The Doctor If...

If you have diarrhea or constipation during the test period.

Other Important Information

Read all instructions that come with the kit carefully before testing begins.

Sources:

Enterix, Inc. "InSure Patient Guide." Clinical Genomics. 2013. 20 Jan 2016.

American Cancer Society. "Can Colorectal Polyps and Cancer Be Found Early" Cancer.org 19 Jan 2016. 20 Jan 2016.

Continue Reading