If I had unprotected anal sex with a positive person, would a negitive 4th generation and a pcr rna combination at 27+ days be conclusive that I was not infected?

Sorry.  At 27 days. Not 27+.

Welcome to our Forum.  I'll be glad to comment.  at 27 or 28 days following an exposure, combination HIV antigen/antibody )4th generation) tests are 99.9% conclusive .  The CDC has published that there are a very small number of cases in which persons did not have positive tests at 4 weeks but then became positive but those cases are very, very rare (neither of us on this forum has ever seen or heard of such a case).  In your situation, if you have also had a negative HIV RNA PCR test, then you can be entirely confident that you were not infected by your undescribed contact.  I would not worry and from the little you have described, see no scientific reason for additional testing for HIV.  EWH---

Thank you doctor.

 Yes, your summary is correct. You should have complete confidence in your test results and be confident that you did not acquire HIV from the exposure you have described. It is time for you to move forward without concern. EWH ---

This is great news. I know I do not have HIV 1 because of my test results.  The 4th generation and rna pcr hiv 1 at 27 days. Do I have to worry about HIV 2? I am assuming that you took this into account?  Am I all clear? I am trying to put all this to rest.

At 4 weeks your results for HIV-2 are more than 99% conclusive.  Context provides further reassurance however.  HIV-2 is simply not a concern in North America as HIV-1 is more than 100 times more common than HIV-1 and those cases are virtually all linked to partners fro. west Africa or Southeast Asia.  I would not worry about HIV-2.  It is simply not realistic.---

Thank you doctor. Last question.

Yes, I urge you to move on.  No further testing needed.---