HIV tests that detect only HIV antibody will not detect an HIV infection soon after exposure, during the window period before the development of antibodies. Most people produce detectable levels of antibody 3 to 12 weeks after exposure. If someone is screened with an HIV antibody test too soon, the result may be negative despite the fact that the person is infected (false negative). If an HIV antibody test is negative but suspicion of exposure remains high, then repeat testing using the HIV antigen/antibody blood test may be required.