What are blood test reactions?

HIV tests are used to detect the presence of the human immunodeficiency virus in serum, plasma, saliva, or urine. Such tests may detect HIV antibodies, antigens, or RNA. In the United States, a number of HIV test kits have been approved by the Food and Drug Administration for diagnosis, prognostic determination, patient monitoring, and screening of blood and tissue donors. The specific tests used may vary from country to country. As of 2006, the standard HIV tests used in the U.S. are extremely accurate.