Health Library Explorer
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z A-Z Listings Contact Us
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Click a letter to see a list of conditions beginning with that letter.
Click 'Topic Index' to return to the index for the current topic.
Click 'Library Index' to return to the listing of all topics.

Colorectal Cancer Screening: Testing for Blood in Your Stool

There are several ways to check for colorectal cancer, and testing for blood in your stool is one of them. These tests can detect signs of colorectal cancer or polyps because sometimes colorectal cancers or polyps bleed into your digestive tract. This blood can then go into your stool or feces. While these tests might sound uncomfortable, there is some good news. They can be done in the comfort of your own home.

What tests are available?

There are 2 main types of tests. They include:

  • Guaiac fecal occult blood test (gFOBT). This uses a chemical to find blood in your stool.

  • Fecal immunochemical test (FIT). This looks for blood in the stool that comes from your lower intestines.

What do I need to know about the tests?

Before you get started, here are some things to know.

  • If you're using one of these tests to screen for colorectal cancer, it must be done every year.

  • These screening tests don’t find cancer. They look for blood in your digestive tract.

  • If the test finds blood in your stool, it doesn’t mean that you have cancer. It could mean that you have polyps, hemorrhoids, diverticulosis, or inflammatory bowel disease. Talk with your healthcare provider after your results to know for sure.

  • It’s possible to have false positives and false negatives. A false positive is when the test shows the possibility of a polyp or cancer when it’s not there. A false negative is when the test doesn’t show cancer or a polyp since it doesn't bleed.

  • If your result is positive, you will need a colonoscopy to look for the cause of the bleeding. Talk with your provider about next steps. They can help you schedule a colonoscopy.

How do I perform the tests?

Luckily, you don’t need to go to a lab to get these tests done. They’re easy to do on your own from home. Your healthcare provider can give you a test kit and any additional information you may need. While these tests are simple, know that they do involve collecting your own stool (poop).

Each test has different instructions, so it's very important to follow them exactly for accurate results. When you’re about to do the test, check that you have all your supplies nearby in the bathroom.

You may need to collect 1 to 3 separate stool samples depending on the type of test. You can gather the stool using a clean container or by draping plastic wrap loosely across your toilet bowl to catch it. Then, use the provided applicator to spread the sample onto the testing kits before sending them as instructed.

Do I need to prep?

The American Cancer Society and U.S. Preventive Services Task Force advise people at an average risk for colorectal cancer start screening at age 45. You may need to start screening earlier if you’re at a higher risk. Your provider can help you determine this.

FIT

If you’re using the FIT, you’re in luck. There aren’t any dietary or medicine restrictions for taking the test. Medicines and foods don’t affect this test.

gFOBT

You need to pay close attention to your eating and other habits if you’re using the gFOBT. Don’t forget that it’s very important to follow the prep instructions in your kit to make sure you get the correct results.

All test kits come with detailed instructions. But certain foods and medicines can affect the results of gFOBT tests. So you might see these general guidelines:

  • Don't eat red meat (beef, liver, or lamb) for 3 days before the test.

  • Don't have more than 250 mg of vitamin C a day (either from supplements or citrus fruits and juices) for 3 to 7 days before the test.

  • Don't use products that contain aspirin or use nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen and naproxen, for 7 days before the test.

Always read the prep kit thoroughly before you test. If you have questions, talk with your healthcare provider. They’re there to help you through the testing process so you’re comfortable doing it at home.

Online Medical Reviewer: Jessica Gotwals RN BSN MPH
Online Medical Reviewer: Sabrina Felson MD
Online Medical Reviewer: Todd Gersten MD
Date Last Reviewed: 5/1/2023
© 2024 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare provider's instructions.
Contact Our Health Professionals
Follow Us
Powered by StayWell
About StayWell | Disclaimer | Terms of Use

Our web site is designed to provide general information to educate users about programs and services, which may be available through our hospitals. The web site is not intended to provide medical advice nor should the information be used to attempt to determine the presence, absence or severity of any illness or medical condition which may be perceived or experienced by the user of this site. If you have or suspect you may have an illness or condition which you believe requires medical attention, we recommend you call your primary care physician. If you believe you are experiencing a medical emergency please call "911" (or your local medical emergency number) or seek immediate care from the nearest hospital Emergency Department. The provision of information to users of this web site is not intended as an inducement or to otherwise influence a person's decision to order or receive any item or service from a particular provider, practitioner or supplier that is reimbursable under Medicare, a state healthcare program (e.g., AHCCS) or any other healthcare plan.

Physicians are members of the medical staff at each facility, but are independent contractors who are neither employees nor agents of Tenet Florida Coastal Division; and, as a result, Tenet Florida Coastal Division is not responsible for the actions of any of these physicians in their medical practices.