The HIV antibody test is a blood test to check if you have AIDS. There are two types of HIV tests, type 1 and type 2, and they are usually done at the same time. There is a window period for the HIV antibody test, which is a period of time from the time of infection to the time of detection of antibodies, usually 2-6 weeks. The most conservative statement used to be that the test could not be fully detected until 12 weeks, which means that if the test is negative for HIV antibodies after 12 weeks, you can rule out the possibility that you have HIV. If the test is positive at 12 weeks or at 2 or 3 weeks, it does not mean that you have AIDS because the test has a certain rate of false positives and further confirmatory tests need to be done.