The time period that starts when a person becomes infected with the human immunodeficiency virus (HIV) and ends when the body makes enough antibodies against the virus or HIV DNA or RNA to be found with an HIV test. For the test that looks for antibodies against HIV, the HIV window period can last from 2 weeks to 6 months. For the HIV DNA or RNA test, the HIV window period is about 9-11 days. During the HIV window period, an infected person may have negative HIV test results but still be able to infect other people.