I made the wrong choice and performed oral sex on a man whom I was not in a relationship with a few months back ( I am female). Now I have no reason to think this man has any STI. But my fear is that I have passed an oral infection on to my boyfriend. I understand that to bed tested orally you need a throat swab, but I figured that if we have sex once a week which includes vaginal and oral sex I could do urine testing. 

My question is, I know that a vaginal swab is the gold standard, but I am too embarrassed to keep going to the OBGYN. So I have ordered tests from websites that use labs. I had a vaginal swab in April which was negative and I have had a negative urine test every month after. The incident happened in march. Are these conclusive? Or is there a chance that I gave my partner an infection that he has yet to give me? 

Are multiple urine tests as good as a vaginal swab? 

Going to your fear of having transmitted chlamydia to your boyfriend:  You are correct that oral chlamydia is rare. Equally important, even when present it is rarely if ever transmitted. In fact, to date there have been very few IF ANY cases of oral chlamydia being transmitted to a sex partner. Over 25 years ago, research found that when males have nongonococcal urethritis (NGU) acquired by oral sex, chlamydia never is the cause -- compared with 30-40% of NGU from vaginal or anal sex. (Here's a link to that research report; note the authors. https://pubmed.ncbi.nlm.nih.gov/9153736/)

The reasons for that study result are now more clear than at the time, with more sophisticated chlamydia tests. Not only are positive throat chlamydia tests rare, but when present more than half the time only chlamydial RNA is detected -- no living bacteria, therefore no possibility of transmitting infection. On top of all that, when positive oral chlamydia tests almost always become negative, even without treatment, within a few weeks.

Finally, you also are correct in believing that if your partner had urethral chlamydia, you probably would have been infected by now. In other words, your negative urine test results are additional evidence that you have nothing to worry about.

Does this all mean oral chlamydia or its transmission to sex partners never happens? No. But it is solid evidence that it is at most a very rare circumstance -- and zero chance, for all practical purposes, that you have it or infected your partner. If you need any more evidence or reassurance, you could go to a lab an anonymously have a throat swab test for chlamydia (which would automatically include a gonorrhea test). But this really isn't necessary. There is no chance your concerns have any basis in reality. Try to stop worrying about it!

I hope these comments are helpful. Let me know if anything isn't clear.

HHH, MD