Since colorectal cancer is second only to lung cancer in the U.S., screening for this disease should start in every one at age 40. After the age of 50, the risk of developing colorectal cancer doubles every 10 years. Detecting blood in the stool is a good indicator of colorectal cancer. Early detection is crucial. It is important in stopping the progression of the disease, as well as treating it. Since fecal occult blood test kits are easy and convienent for patients to use at home, they have become important in screening for colorectal cancer.