Hello Drs. I had an encounter with a friend (Female)  11/27/21 used condom and for a brief moment I took off the condom and inserted my penis in her vagina for 4-8 “strokes” she also did give me oral sex. She says she is clear from sti/stds cause she goes for yearly check ups. She said her last encounter was months back using “protection” and was in a 10 year relationship. What tests should I check myself from this encounter? And at how many days/weeks are they considered conclusive? 

Welcome to our Forum and thanks for your questions.  I’ll be glad to comment.  The encounter you describe was low risk.  My sense is that your partner is unlikely to be infected and even if she was, most exposures do not result in infection.  Nonetheless I support your plan to be tested for the most common STIs.  From your post it sounds like only your penis was exposed, both through vaginal sex and receipt of oral sex.  If this is the case, I would suggest that the most important testing is to get a urine test for Gonorrhea and chlamydial infections any time more than 3-4 days following exposure.  ---

I’ve always been wanting to ask. Why would I not worry about HIV, syphillis, or HEP B/C? Do they transmit differently than gonorreah/chlamydia? How so? 

My recommendations and comments are based on epidemiologic facts.   Both gonorrhea and chlamydia are relatively common amongst STI‘s in heterosexual women. On the other hand, HIV and syphilis remain diseases which are far more likely to occur amongst men with other men as sex partners and really occur in women. When these infections occur in women they occur predominantly amongst women who regularly use illegal drugs.  When you add those statistics to the fact that most exposures do not result in infection ( HIV transmission occurs on average once per every 1200 acts of intercourse with untreated, HIV infected women), there is a little risk that you were exposed or, if exposed, infected with either HIV or Syphilis.---

So to conclude. In your professional suggestion. I should only test for chlamydia/gonorrea 2-4 days after exposure and those results should be conclusive?.. no need for hiv/syphilis/hep b/c and I shouldn’t be concerned about the pregnancy portion of the encounter?… lastly does the use of marijuana (smoking) affect plan b? 

Correct.  Of course you can test for anything that you wish but I have provided the information regarding the STI’s which are most likely. I hope you find it helpful. Similarly, the risk that your partner will become pregnant following the encounter you described is very, very low.---