China’s AIDS Regulations require routine testing for hepatitis B, hepatitis C, syphilis and HIV before surgery or invasive procedures, commonly known as the “Preoperative Four”. This is a prudent consideration for patients, medical care and hospital management in all aspects. 1. For patients: Screening helps to comprehensively assess the condition and select appropriate surgical methods and contingency measures to ensure the smooth implementation of surgery and facilitate recovery. Low immunity in HIV-infected patients and possible coagulation disorders in hepatitis patients require special preparation prior to surgery. In addition, early detection of the disease enables early treatment and response. 2. For medical workers: Examination is a protective measure. Doctors and nurses often run the risk of accidentally having their hands pierced by needles, being cut by scalpels or having blood (body fluids) splashed in their eyes. Pre-operative examinations allow health care workers to avoid infections caused by occupational exposure to the maximum extent possible with limited resources. 3. For hospitals: As legal evidence of the occurrence of medical accidents requires proof of preoperative infection status. In case an infection is found after surgery, how to characterize whether it is a problem of the patient itself or a medical source infection? The preoperative examination results will be important evidence. 4. Finally, from the public’s point of view: the detection of infected patients with important infectious diseases through pre-surgical screening is important for controlling disease epidemics. Therefore, one should not be afraid and worried about the screening, it is an initiative that has all the benefits but no harm.