There are multiple options available for CRC detection involving the detection of blood in fecal test (or microscopic examination of fecal hemoglobin), the flexible sigmoidoscopy and colonoscopy. Each of these has advantages and disadvantages. Specifically, the microscopic examination of fecal hemoglobin although reduces mortality by 16% by CRC nevertheless exhibits low sensitivity to detect polyps and cancerous lesions in the distal colon and small specificity thus be, in economic terms, negative test to be used in mass screening. Regarding the flexible sigmoidoscopy, this is a test clearly faster and safer than colonoscopy but with small percentage of patient compliance, efficacy clear depended on the quality of bowel preparation and most importantly, it can not see the whole intestine. Computed tomographic colonography is another method of finding new precancerous lesions but because of the short diagnostic accuracy compared to the colonoscopy and radiation, is not recommended for mass screening.