This is a follow up to my last question. I had an unprotected sexual encounter on 12/19 with a person of unknown status albeit likely low risk.  My plan was to wait until the 6 week mark to be retested but my anxiety got the better of me. 

I had a 4th gen Ab/Ag HIV test yesterday 1/15 (27 days after encounter) which was “non-reactive”. Although I feel relieved I just wanted your opinion if you still think I should proceed with a confirmatory test in another 2 weeks? 

Thanks again for all you do.......it’s important work and much appreciated from one health professional to another. 

Indeed you should feel relieved:  there is no chance you have HIV. The test is around 98% conclusive at 4 weeks (with no difference between 27 and 28 days). The chance you caught HIV, based on the information discussed in your previous thread, was no higher than one in a million and probably a lot less than that. Now with a 98% conclusive test, the chance you have HIV is no higher than 1 in 50 million. I hope you'll agree that's zero for all practical purposes. But if you feel you need a truly 100% conclusive test result, you'll need to have the same test 6 weeks or more after the event. (If somehow I were in your situation, or if I were advising someone personally close to me, I would have not advised HIV testing at all, and certainly would not feel a need for another test at this point.)

I hope these comments are helpful. Best wishes.

HHH, MD