The HIV RNA test is highly accurate at providing accurate results when taken during the test's optimal window period. The window period refers to the time after exposure during which the disease can be detected by the test. For the HIV RNA test, that period of time is 10–33 days after exposure. When the test is applied within the 9-11 day window, the accuracy is approximately 95%–99% but will increase to approximately 99% after 28 days.