What to know about at-home screening tests for colorectal cancer

Screenings for any cancer can be anxiety-provoking but screening for colorectal cancer, the third most common cancer diagnosed in the U.S., is especially dreaded. It boils down to generalized fear, embarrassment, fears of undergoing sedation, taking time off from work, the prep may be unpleasant (this has improved), and worries over the test being painful (usually not). 

However, since the acceptance of telehealth and home monitoring of blood pressure for heart disease and blood glucose for diabetes, at-home screening for colorectal cancer has gained acceptance and approval for many years. Not everyone needs to do an outpatient colonoscopy procedure in a clinic. Today, a large percentage of us can do this test in the comfort and privacy of our homes. 

But does this mean at-home screening for this common disease is right for everyone?  In the case of someone at average risk for colorectal cancer, it’s reasonable to consider this alternative screening method. But, a regular colonoscopy is still highly recommended for anyone with a family history of colorectal cancer, has symptoms of the disease, or has a condition like inflammatory bowel disease.  Always consult with your primary care physician for their advice on which method is best for you.

Differences between colonoscopy and at-home screening for colorectal cancer

There are differences between a colonoscopy conducted usually in an out-patient clinic and an at-home screening for colorectal cancer.


  • Traditional Colonoscopy:


Let’s look first at colonoscopy. A colonoscopy is a comprehensive procedure that allows a doctor to view the inside of your colon.  The age guidelines have been lowered from age 50 to age 45 to begin colon cancer screening, and then every ten years after that until age 75, if no polyps are found or more often if a person has a higher risk of this disease. The doctor will snip it out if anything suspicious is detected during the procedure, such as polyps or a suspicious growth. 

The prep for the procedure has been a contentious reason why some people prefer to avoid this screening test. First, you drink liquids to clear out your colon so the doctor has a clear view of this organ. A long, flexible tube is passed into the colon during the procedure. At the end of the tube is a tiny video camera for viewing the colon walls and surgical instruments in case needed to remove polyps or suspicious growths. 

Most colonoscopies take between 30 to 60 minutes and occasionally are unpleasant. However, colonoscopies can detect at least 95% of cancers and are a more sensitive test for identifying colon cancer. 


  • At-home screening test for colorectal cancer


At-home testing is available for those who refuse to do the prep for a colonoscopy. While this test is not as sophisticated or as accurate as a colonoscopy, it has increased the number of people using these tests for colorectal cancer screening since the FDA approved it. 

Currently, there are three types of at-home screenings tests for colorectal cancer recommended by the U.S. Preventative Services Task Force:

  1. Guaiac Fecal Occult Blood Test (gFOBT) – This test uses chemicals to find blood in the stools and needs to be done yearly.
  2. Fecal Immunochemical Test (FIT) – This test uses antibodies to detect blood in stool and must be done yearly. 
  3. Multitarget Stool DNA (mt-sDNA) – This test, also known as Cologuard or FIT-DNA test, is able to identify DNA from cancer cells in the stool and has a FIT component to look for blood. It must be done every three years.

Once blood or stool samples are collected, the samples are sent to either your doctor’s office or a lab to be analyzed for signs of colorectal cancer. 

Your doctor will need to prescribe the test to receive an at-home screening test. For those on Medicare, it will pay for the test as long as you don’t have symptoms of colorectal cancer. Anyone without a doctor can go online and order a FIT-DNA test (at www.cologuard.com), and the test maker will arrange for a telemedicine visit with a physician to evaluate your health and then prescribe the test. You can also buy some gFOBT or FIT tests online or over the counter for $10 to $25. However, these tests may not be as accurate as what is prescribed by your doctor.  

Testing accuracy among each at-home test varies. The most sensitive at-home test is the FIT-DNA. It has a 92% accuracy if cancer is present, while the FIT test’s accuracy is around 80% to 82%. The least sensitive at-home test is the gFOBT test.  It only identifies between 20% and 50% if colon cancer is present.  Because of its unreliability and inaccuracy, the gFOBT test is no longer used. 

Even if a person uses an at-home test kit, if it suggests you may have colorectal cancer, you will still require a colonoscopy for a diagnosis. Therefore, a gastroenterologist will do a follow-up colonoscopy to accurately locate and remove the tumor(s) or precancerous polyps. Even if your at-home test is negative for cancer, you should be aware of potential signs of colon cancer which include:

  • The bowel feels as though it’s not emptying completely
  • Blood in the stool
  • Stools that are narrower than usual
  • Frequently feeling full or bloated
  • Weight loss with no known reason

Colon cancer caught early can be cured. The best way to catch it early is to be screened for it with a colonoscopy or an at-home test.  If you are 45 or older or have a family history of colon cancer, talk to your doctor of when to start screening for it and which screening test is right for you. 


Dr. David Samadi is the Director of Men’s Health and Urologic Oncology at St. Francis Hospital in Long Island. He’s a renowned and highly successful board certified Urologic Oncologist Expert and Robotic Surgeon in New York City, regarded as one of the leading prostate surgeons in the U.S., with a vast expertise in prostate cancer treatment and Robotic-Assisted Laparoscopic Prostatectomy.  Dr. Samadi is a medical contributor to NewsMax TV and is also the author of The Ultimate MANual, Dr. Samadi’s Guide to Men’s Health and Wellness, available online both on Amazon and Barnes & Noble. Visit Dr. Samadi’s websites at robotic oncolo gy and prostate cancer 911. 

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