HIV tests are very accurate, but no test can detect the virus immediately after infection. How soon a test can detect HIV depends upon different factors, including the type of test being used. There are three types of HIV diagnostic tests: nucleic acid tests (NAT), antigen/antibody tests, and antibody tests. HIV testing can be done by Drawing blood from a vein, A finger prick blood sample, An oral fluid swab, A urine sample. HIV transmission is only possible if these fluids come in contact with a mucous membrane or damaged tissue or are directly injected into the bloodstream (from a needle or syringe). Mucous membranes are found inside the rectum, the vagina, the opening of the penis, and the mouth. Having anal or vaginal sex with someone who has HIV without using a condom or taking medicines to prevent or treat HIV. Sharing injection drug equipment (works), such as needles, with someone who has HIV. HIV can also spread from a woman with HIV to her child during pregnancy, childbirth (also called labor and delivery), or breastfeeding. This is called mother-to-child transmission of HIV.