How soon after unprotected sex can you get a blood test for hiv?

18- 45 days after exposure. During that time think of having safe sex now and in the future.

A blood test can usually detect HIV infection 18-45 days after an exposure. No HIV test can detect HIV immediately after infection. If a person thinks she’s been exposed to HIV in the last 72 hours, it’s a good idea that she talk to a health care provider about a medication that could lower the risk of infection called post-exposure prophylaxis (or PEP) as soon as possible.