Fecal immunochemical test (FIT)
Immunochemical fecal occult blood test; iFOBT; Colon cancer screening - FIT
The fecal immunochemical test (FIT) is a screening test for colon cancer. It tests for hidden blood in the stool, which can be an early sign of cancer. FIT only detects human blood from the lower intestines. Medicines and food do not interfere with the test. So it tends to be more accurate and have fewer false positive results than other tests.
How the Test is Performed
You will be given the test to use at home. Be sure to follow the instructions provided. Most tests have the following steps:
- Flush the toilet before having a bowel movement.
- Put the used toilet paper in the waste bag provided. Do not put it into the toilet bowl.
- Use the brush from the kit to brush the surface of the stool and then dip the brush into the toilet water.
- Touch the brush on the space indicated on the test card.
- Add the brush to the waste bag and throw it away.
- Send the sample to the lab for testing.
- Your doctor may ask you to test more than one stool sample before sending it in.
How to Prepare for the Test
You do not need to do anything to prepare for the test.
How the Test will Feel
Some people may be squeamish about collecting the sample. But you will not feel anything during the test.
Why the Test is Performed
Blood in the stool may be an early sign of colon cancer. This test is performed to detect blood in the stool that you cannot see. This type of screening can detect problems that can be treated before cancer develops or spreads.
Talk with your doctor about when you should have colon screenings.
A normal result means the test did not detect any blood in the stool. However, because cancers in the colon may not always bleed, you may need to do the test a few times to confirm that there is no blood in your stool.
What Abnormal Test Results Mean
If the FIT results come back positive for blood in the stool, your doctor will want to perform other tests, usually including a colonoscopy. The FIT test does not diagnose cancer. Screening tests such as a sigmoidoscopy or colonoscopy can also help detect cancer. Both the FIT test and other screenings can catch colon cancer early, when it is easier to treat.
There are no risks from using the FIT.
Itzkowitz SH, Potack J. Colonic polyps and polyposis syndromes. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger and Fordtran's Gastrointestinal and Liver Disease: Pathophysiology/Diagnosis/Management. 10th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 126.
Lieberman DA, Rex DK, Winawer SJ, Giardiello FM, Johnson DA, Levin TR; United States Multi-Society Task Force on Colorectal Cancer. Guidelines for colonoscopy surveillance after screening and polypectomy: a consensus update by the US Multi-Society Task Force on Colorectal Cancer. Gastroenterology. 2012;143(3):844-857. PMID: 22763141
Lin JS, Piper MA, Perdue LA, et al. Screening for colorectal cancer: updated evidence report and systematic review for the US Preventive Services Task Force. JAMA. 2016;315(23):2576-2594. PMID: 27305422
National Cancer Institute website. Colorectal cancer screening (PDQ) - health professional version.
Last reviewed on: 8/1/2017
Reviewed by: Subodh K. Lal, MD, Gastroenterologist with Gastrointestinal Specialists of Georgia, Austell, GA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.