We know that colonoscopy screening can improve life expectancy by detecting colorectal cancer at an early stage. However, the question is how to develop an effective and convenient screening program that is medically successful, non-invasive and inexpensive, and can accurately diagnose asymptomatic disease at a curable stage. Currently, the most important methods of screening for colorectal cancer are fecal occult blood test and colonoscopy. The fecal occult blood test is a microscopic examination of blood in the stool, using an enzymatic reaction with hemoglobin, an oxygen-carrying protein in the blood, to test for bleeding in the stool. Because colon cancer bleeds more often than normal colon mucosa, the cancer bleeds about two-thirds of the time during the week and just usually goes unnoticed. However, tumors in the colon may bleed intermittently, so one stool test for occult blood does not confirm that there is no bleeding in the intestine, and its reliability is significantly higher if the test is repeated several times without occult blood, so the larger the sample size of the test at different times, the higher the detection rate of positive results. In general, we expect screeners to send stool for testing once in each of 3 consecutive weeks, which will increase the detection rate. The fecal occult blood test is a good screening test, inexpensive and easy to perform, and many hospitals abroad now allow screening subjects to perform the test themselves at home and then simply tell their doctor the results. In addition, even if the fecal occult blood test is performed three times a year, the current fee is only $36, so it does not cause any financial burden to the screened person. False-positive fecal occult blood test can produce false-positive results, for example, hemorrhoids, gastric ulcers and even bleeding gums may cause false-positive results, so although the fecal occult blood test is sensitive, its accuracy is not very high. In China, colonoscopy is not a very expensive test, and the general cost of colonoscopy is about 300 RMB. Does health screening increase the financial burden of patients? Let’s try to calculate an account to see if it is cost-effective. Nowadays, the general screening method is to check fecal occult blood test 3 times a year and colonoscopy every 3-5 years, so the cost for a person who starts screening for colorectal cancer from the age of 40 to the age of 75 is: 35 years fecal occult blood cost 36×35=1260 RMB, every 3 years colonoscopy cost: 300×35/3=3500 RMB, total 4760 RMB, which is not a heavy burden for any person. It is not a heavy burden for any person. But when a person needs surgery, radiotherapy and chemotherapy for colorectal cancer, the cost of surgery is usually about 35,000 yuan, and the cost of chemotherapy for 6 courses is at least 30,000 yuan, so it costs at least 60,000 yuan. So even from a health economics point of view, it is most cost effective to get screened for colorectal cancer.