1.  If one has an heterosexual exposure with an unknown person and is tested at 28, 42 and 73 days using a quest lab based 4th gen hiv test is that more than enough to be deemed conclusively negative. 

2. Any circumstance that requires further testing for hiv?

3. Considering the cdc has changed their verbiage to 45 days as the day for one to tell for sure they do not have Hiv, why does this forum still say 42?

4. Do they mean you have to test exactly at 45 days, would that mean a 73 day test is my valid?

5. If someone had homosexual sex as receptive partner with a confirmed positive person would the above results still be enough to be deemed negative?

6. What is an elite controller and would the antigen part of a 4th gen still diagnose an elite controller?

7. Knowing what you know as a veteran medical professional, if you were somehow in a situation such as heterosexual sex with an unknown partner would you also stop testing after the above three negative tests?

8. Could a 4th gen test be wrong three times at different intervals as above?

That’s all I have for know and thank you for your time. 

1,5. Yes, those reults would be comclusive, regardless of the nature of the exposure. Same for heterosexual exposures, sex with other men, shared drug injection needles, or any other exposure.

2. If the exposed person has taken anti-HIV drugs for pre- or post-exposure prophylaxis (PrEP, PEP) that doesn't work, the time to positive testing may be delayed. This is only theoretical, but in that situation most experts advise testing at 3 or even 6 months. 

3. There is no meaningful difference between 42 adn 45 days, and 42 is 6 weeks -- and it's easy to just say testing at 6 weeks is sufficient.

4. The testing times mean from that time onward. Once the test is positive, it remains positive for as long as the infected person lives.

6. Elite controllers are those few (under 1%) of people infected by HIV who do not have progressive immune deficiency and rarely progress to overt AIDS. Test results are probably equally reliable at the same times after exposure.

7. If somehow I were in this situation, or if I were advising someone personally close to me, for some exposures I would not recommend testing at all, e.g. low risk partner, condom properly used, etc. If significant risk, I would say a negative Ag/Ab (4th generation) test anytime at 4 weeks or more after exposure is sufficient. If the risk were particularly high, such as unprotected vaginal or anal sex with a known infected partner, I would also advise testing at 6 weeks, but never any later than that unless PEP or PrEP were involved as discussed above.

8. There is no realistic chance that someone with those test results in fact has HIV. But if you would like to say more about the exposure you are concerned about, I might have more detailed advice (and perhaps reassurance).

I hope these comments are helpful. Best wishes and stay safe--  HHH, MD

I have however taken some antibiotics over the course of the last three months. 

Would I need to continue testing as I fear for my regular partner. 

I have seen on this forum that it’s recommended that a single 4th gen is enough at 42 days, is that correct?

My question #4 was based on my understanding of a positive result but rather was that if someone is negative on 42 days but cdc says 45 does that make the validity of a negative at 73 days less considering cdc says 45 days. 

Hope that’s not confusing. 

Thank you

For those reasons, you did not need HIV testing at all. But your negative test results prove you did not catch HIV and can safely continue unprotected sex with your regular partner. You do not need to continue testing.

"I have seen on this forum that it’s recommended that a single 4th gen is enough at 42 days, is that correct?" That's what we discussed above. Is there something about it you don't understand.

" cdc says 45 does that make the validity of a negative at 73 days less?" I don't understand what you're asking. How can a negative results at one time make a later test even less reliable? Every test later than an earlier one is at least equally reliable as the original test.

A few follow up questions 

1. You are right I do not remember any vaginal intercourse but it wouldn’t matter as my tests have proved I’m not infected?

2. Have you ever seen or heard of a neg 42 day  4th gen later being positive?

3. Has the cdc officially changed down to 45 days for conclusive tests when using a 4th gen. Is that an official change? I have seen some of the posts here where you referenced the study that prompted the change but it doesn’t really allow you to view anything but rather just gives a paragraph synopsis. 

4. You are certain that I can and should continue unprotected relations with my regular partner based off my test negatives. I have not gone outside the relationship aside from the event I described. 

Thanks for all your answers they have really helped my tremendous anxiety. 

2) No, not in my experience.

3) I'm not sure what recommendations CDC considers "official".

4) Yes, I am certain. Look at it this way. Let's say there was a 1 in 1000 chance your partner had HIV and 1 in 1000 chance you could have been infected. The chance you caught HIV therefore would be 1 in a million (1/1000 x 1/1000). Now let's assume your 28 day test was "only" 99% accurate, or 1 chance in 100 it missed an HIV infection. After that result, the chance you had HIV became 1/1,000,000 x 1/100 = 1 chance in 100 million. That's zero for all practical purposes:  your chance of winning a major lottery is a lot higher than that. And your additional tests beyond 28 days were even more accurate.

I'm glad the discussion has been of help. That's why we're here. That concludes this thread. (Please don't start a new one about this exposure and your risk and testing for HIV. There is nothing you can think of that would change my advice. If further questions arise, re-read this thread. Almost certainly any further questions you may have already were answered.)

Best wishes and stay safe!