QUESTION
I had unprotected anal sex. I was the bottom, and he didn't come inside. I just want to know the risk and if should I seek help? Should I take a HIV test? Any suggestions?

ANSWER
Unprotected receptive anal sex carries the highest risk for getting HIV infection. HIV can be found in pre-cum, the fluid that sometimes comes out before ejaculation, so even if the top does not ejaculate inside there is still a risk of infection. Some doctors estimate that the risk of infection during receptive anal sex is anywhere from 1 in 50 to 1 in 500 and might even be higher (1 in 20) in HIV-infected patients who have been infected very recently (acute HIV infection).

Bottoms can also get other STDs like rectal gonorrhea or rectal chlamydia where ejaculation is not necessary to spread infection.

We recommend that sexually active MSM with multiple partners get HIV tested and STD testing at all exposed anatomic sites (throat/anus) every 3 to 6 months. Be sure when getting STD tests of the throat or rectum that DNA or molecular tests are used. Those DNA/molecular tests are much more accurate than traditional culture tests. Both require a doctor to use a swab to collect a sample inside the back of the throat or inside the rectum. Major commercial laboratories like LabCorp and Quest Diagnostics now routinely offer those types of STD screening tests.

In addition, those with recent potential exposures to HIV should get an HIV test that includes HIV RNA screening. HIV RNA screening is another DNA/molecular test that is much more accurate than a traditional HIV antibody test and can identify infection as soon as 7 days after exposure.

It is always a good idea to get tested for HIV and other STDs before having unprotected sex. However, this isn’t always realistic, so if you are nervous about your status, the best thing to do is come in for a test so you can know for sure. For more information on STD testing, visit http://SFCityClinic.org or http://STDTest.org (includes DNA/molecular testing and HIV RNA testing) for places in San Francisco or call the CDC National Hotline for services near you: 1-800-CDC-INFO.

For read more about HIV testing, see http://sfcityclinic.org/stdbasics/hivaids.asp.

To your health,
Dr. K