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How soon after exposure can HIV infection be detected?
With the HIV antibody tests used in New York State, virtually all people who are infected will test positive within one month of being infected. Most people will test positive even sooner.
[COMMENTS: TALKING ABOUT MOST.]
The period between the time of infection and the time that a HIV antibody test can detect the infection is called the window period. During the window period, an infected person does have HIV and can pass HIV to other people, even if his or her HIV antibody test is negative.
So, if you HIV antibody test is negative, you can be sure that you do not have HIV only if you have not engaged in any HIV risk behaviors (such as having unprotected sex or sharing needles) during the past three months.
[COMMENTS: TALKING ABOUT ALL (YOU CAN BE SURE THAT YOU DO NOT).]
A PCR (Polymerase Chain Reaction) test looks for HIV directly instead of detecting antibodies. This test can find HIV infection as soon as the person is infected. It is usually used to find HIV infection in newborns. A different type of PCR test, called a viral load test, is used to measure the amount of HIV in the blood of someone who is already known to be infected. Doctors may suggest and HIV PCR test if they think a person has been infected with HIV in the past few days or weeks.