The four preoperative tests include Human Immunodeficiency Virus Test, Hepatitis B Virus Surface Antigen Test, Hepatitis C Virus Antibody Test and Syphilis Spirochete Antibody Test. 1. Human Immunodeficiency Virus (HIV) test: It is a test for HIV, which is not infected by ordinary contact, and the most common ways of transmission are sexual contact, blood transmission, and mother-to-child transmission. 2. Hepatitis B Virus Surface Antigen Test: The significance of the test is to check whether you are infected with hepatitis B virus. 3. Hepatitis C Virus Antibody Test: Through the test, it can show whether the body contains the antibody of Hepatitis C Virus, and initially screen whether the body is infected by Hepatitis C Virus. 4. Syphilis spirochete antibody test: After the syphilis spirochete invades the human body, specific antibodies will appear in the serum, which is used to detect whether there is any syphilis infection. Syphilis is a sexually transmitted disease. Because surgery and preparatory work may have invasive operations, there is a possibility of infection with the above virus, in order to distinguish between preoperative and postoperative infections, it is necessary to do these four tests before surgery.