Test Details: The HIV antibody test advised by the CDC is the HIV-1/2 antigen/antibody combination immunoassay test. This test is to confirm sero status of patient for HIV-1 and HIV-2. Antibodies against HIV-1 and HIV-2 are usually not detectable until 6 to 12 weeks following exposure and are almost always detectable by 12 months. They may fall to undetectable levels (ie, seroreversion) in the terminal stage of AIDS when the patient's immune system is severely depressed.