AIDS requires testing, and the initial screening test is for HIV antibodies. The results of this test can be tested at hospitals above the second level as well as at the third level. If the initial screen is positive for HIV antibodies, this blood will be sent to a qualified confirmatory laboratory for a confirmatory test. The source of HIV infection is the HIV-infected person and the person with AIDS. HIV patients who are asymptomatic but have positive serum HIV antibodies are an important source of infection. There are three main recognized transmission routes: 1) sexual contact transmission; 2) transmission by blood contact; 3) mother-to-child transmission. There are others, if one is receiving an organ transplant from an HIV-infected person, artificial insemination or contaminated devices, etc. can be at risk of being infected.