HIV1+2 refers to HIV type 1 and HIV type 2. HIV type 1 is prevalent worldwide, while HIV type 2 has a more limited epidemic, mainly in western Africa. HIV type 1 is prevalent in China, with a small number of people infected with HIV type 2 in some areas. When performing an HIV test, both types of virus must be included in the test in order not to miss HIV. This test is seen in clinical practice mainly from the laboratory test, and when testing for HIV antibodies, both types are tested at the same time so that the type of HIV is not missed.