Fecal occult blood test (FOBT). For this test, you put tiny samples of your stool on a special card or cloth and send it to a lab. The lab uses chemicals to find blood that can't be seen with the naked eye. With some test kits, you can add the chemicals yourself at home. For several days before the test, you can't eat certain foods, and you have to stop taking some medicines.
Fecal immunochemical test (FIT), also called an immunochemical fecal occult blood test (iFOBT). For this test, you take a sample with a brush and dab it onto a special card. This test may be easier to do at home than the FOBT. There are no drug or food restrictions, and collecting a stool sample may take less effort.
Stool DNA test (sDNA). Instead of looking for blood in the stool, this test looks for abnormal DNA from cancer or polyp cells. For this test, you collect all of the stool from one bowel movement and put it in a special box that you mail to the lab. There are no drug or food restrictions. Of the three tests, this one has the easiest instructions.
Blood in the stool may be the only symptom of colorectal cancer, but not all blood in the stool is caused by cancer. Other conditions that can cause blood in the stool include: