The answer to this question depends on the kind of sex you’re having. A doctor will usually test you for HIV, do a blood test for syphilis, and a urine test for STDs in your genitals. If you have oral sex, you should make sure your doctor swabs your mouth to check for STDs there, and if you bottom, you should make sure they swab your butt too.
It’s important to also get tested for Hepatitis B at least once, as well as for Hepatitis C, especially if you are HIV-positive.
Check out this one minute video from Greater Than AIDS for more.