Currently, there are two tests that are generally accepted to screen for colon cancer; a fecal test every two to three years and colonoscopy which is suggested once every 10 years. Colonoscopy allows accurate diagnosis and the doctor can get a sample which can be sent to the lab. Unfortunately, it requires a 24 hour prep and anesthesia as well as a facility and a doctor to perform the test. This makes it a poor screen as you cannot screen millions easily. Fecal tests used initially in Europe allows the inexpensive screening of millions and only those who have a positive test are then recommended to have a colonoscopy. The benefit is that you can screen millions and only those who are positive have the colonoscopy. This is a far more efficient way to diagnose colon cancer cost effectively and has a proven track record as it gains favor in the USA. Find out more about Cologuard Doctors now have a third way of diagnosing colon cancer which involves a simple blood test that can be done during an annual physical exam. As reported by the NY times, this technology is new and works because cancers developing in the colon shed DNA fragments that can be detected in the blood. This test was reported by the New England Journal of Medicine by the NY Times recently. The test has a 10 percent error rate but detected 87 percent of cancers at an early stage. The test searches for this DNA. The test is called shield and is made by Guardian Health. Read more in the NY Times article here.