What you can expect

By Mayo Clinic Staff

There are several types of fecal occult blood tests, each with a different approach to collecting and testing stool. They include:

  • Guaiac fecal occult blood test (gFOBT). Your doctor typically gives you a test card with room for two or three samples or two or three test cards. You collect a stool sample from each of two or three bowel movements in a clean container, usually taken on consecutive days, and then use an applicator stick to apply a smear of stool to a specific area of a card. After the samples are dry, you return them to your doctor or a designated lab, by mail or in person.
  • Flushable reagent pad or tissue. You can get this kit at a store without a prescription. You place the pad or tissue in the toilet bowl after a bowel movement, usually on three consecutive days. The pads change color when blood is present. You then report the changes to your doctor, usually on a mail-in form.
  • Immunochemical fecal occult blood test (FOBT or FIT). The collection method for this test may depend on the manufacturer, but typically, you use a special spoon or other device to collect a sample of stool and store it in a collection container that comes with the test kit. The collection container is then returned to your doctor or a designated lab, by mail or in person.

    Immunochemical testing is newer than gFOBT. It doesn't require any dietary restrictions before sample collection and testing can often be performed on a random stool sample. Immunochemical testing is also more sensitive than gFOBT.

For accurate results, it's important to return the samples promptly.

Jun. 18, 2011