Thanks for running a great forum. I had unprotected anal as top with another guy as a one off . Who said he was negative at his test 2 weeks prior - he has now become positive from an encounter after me. I took a biosure Uk home test(finger prick) 1 day short of 8 weeks at 55 days - it was negative. Is this conclusive ? This test was back in may and I’ve recently had a big flare of existing psoriasis and some sites say that can be an indicator.  I’ve read from yourselves that 8 weeks is conclusive yet the biosure site says it’s a 2 nd generation test ? Need I be worried ? Many thanks again 

I certainly understand how this situation concerns you -- in fact, since it's often difficult to know exactly when and from whom any particular HIV infection is acquired, perhaps there was concern that you were the source of your partner's HIV infection. That concern definitely is no longer warranted (if it ever was); your negative test proves that. And if his belief about the source of his infection is correct, i.e. assuming he didn't have it at the time of your exposure, you were not at risk. On the other hand, of course you were right be be concerned and to be tested, and you're close to conclusive results from that standpoint. In a world dominated by third and fourth generation tests, a second generation one can seem ancient -- but even those tests are quite good, with probably ~98% of newly infected people having positive by 8 weeks (and one day short should make no difference). However, it would make sense for you to have a final test at 12 weeks. You can expect it to remain negative. (Or have a gold standard test now, i.e. an AgAb [4th generation], which of course would be conclusive now.)

As for your psoriasis flare, it cannot be due to HIV in the face of a negative antibody test. It isn't HIV infection per se that causes symptoms of a new infection, but the immune response to it -- which means that even when negative testing doesn't totally exclude infection, it does prove that any symptoms are not due to HIV.

There is at least a small elephant in this room -- your decision to have unprotected anal sex with a possibly infected partner. If you mutually assured each other you didn't have HIV, then as a one-off event, as you describe it, it was lower risk for HIV (but of course still high risk for other STIs). But as you found, it's difficult to know for certain about HIV status:  ironically, it would have been safer with a partner known to already have HIV, if on effective anti-HIV treatment with low viral load. Almost certainly you dodged the bullet this time -- but hoping you'll keep this little lecture in mind going forward.

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

HHH, MD

I’ve had this psoriasis before - but thought I would ask anyway - the encounter didn’t last long, and didn’t actually “finish” -  maybe half an hour and like I said, he said he didn’t test positive until august but I know I shouldn’t take someone’s word. I suppose I’m getting confused with all the generation of tests and window periods as I saw in another post about manufacturers having to overestimate their window period for legal reasons. It states on the nhs that these tests are the same as rapid tests used in clinics so that confuses me more - then all this worry is making the psoriasis worse

That completes the two follow-up exchanges included with each question and so ends this thread. I hope the discussion has been useful. Best wishes and stay safe.