Fecal occult blood test (fobt)

The guaiac fecal occult blood test (gFOBT) is used to screen for colorectal cancer. Cancer in the colon or polyps in the colon are more likely to bleed than normal colon tissue is. This test uses a chemical to check for very small amounts of blood in the stool.

If signs of blood are found in the stool sample, more tests, such as a colonoscopy, will be done to find the cause.

A guaiac fecal occult blood test is done to look for signs of colorectal cancer and other types of gastrointestinal problems. These include hemorrhoids, anal fissures, and colon polyps, which can cause blood in the stools.

The test isn't able to diagnose colorectal cancer. If a gFOBT finds blood in the stool, you may need more tests to find the reason for the bleeding.

You can check for blood in your stool at home. There are different types of home tests you can use. Make sure to follow the instructions that come with any test. For most tests, you will use stool samples from three different bowel movements over three different days.

For any home test, follow these guidelines:

• Check the expiration date on the package. Don't use a test kit after its expiration date.
• Store the test kit as instructed. Many kits have to be stored in a refrigerator or cool place.
• Follow the instructions exactly. Do all the steps in order, without skipping any of them. Be aware of any special things you need to do before the test. This may include not eating certain foods or limiting your physical activity.
• After you finish your test, follow the instructions that you were given for returning the test.

For a gFOBT test, you put a small sample of stool a card that comes with the kit. You return this to your doctor or a lab.

• Some kits tell you to use a special cloth to wipe with after a bowel movement. After you wipe with the cloth, you put the developer solution on it to check for a color change that means there is blood in the stool.
• Other kits have a special test pad that you place in the toilet after a bowel movement. The pad will change color if the stool has blood in it.

Before you do a guaiac fecal occult blood test, you may need to avoid certain things for 2 to 3 days before the test. They may cause false test results. The things to avoid are:

• Eating red meat. Chicken, turkey, or fish will not affect the test.
• Consuming more than 250 mg of vitamin C from supplements or food.

You may also need to avoid aspirin (or products that contain aspirin) and nonsteroidal anti-inflammatory drugs (NSAIDs) before the test. Talk to your doctor before stopping any medicines.

Don't do the test during your menstrual period or if you are having bleeding from hemorrhoids. And don't test a stool sample that has been in contact with toilet bowl cleaning products that turn the water blue.