I tested via an Alere Determine HIV Ag/Ab rapid  test on Friday, June 30, 2017 -[22 days later]. It was non-reactive for both P24 Antigen and the Antibody. This was a rapid test.  I plan on getting tested again on Monday, July 10 [via a online lab site that does the 4th Generation test] with Quest Labs.  

Questions:

1. Would p24 or antibody have shown by the 22 days?  Luckily I never had ARS or symptoms.

2. Should I have a HIV RNA test done regardless?

Thanks.

First, congratulations on your obvious dedication to sexual safety in regard to HIV. As you likely know, many men having sex with men these days are foregoing condoms with partners who are on treatment, or with an intent to use PEP themselves. You're doing all the right things, including speaking with your partner(s) about HIV status before having sex. Condoms do fail from time to time, but your overall approach means you are at very low risk for HIV. And for this exposure, your partner being on PrEP assures almost no chance of HIV transmission even if he were infected, which almost certainly he is not (because of the PrEP). So even with no condom protection at all, and had he ejaculated in your rectum, there would have been little or no risk.

1) The Determine test is roughly 70% conclusive at 3 weeks, so the negative result is moderately reassuing, in addition to nearly zero risk from the exposure. Your planned lab-based test (assuming it also is an Ag-Ab/4th gen test) will be close to 100% conclusive at about 4.5 weeks after exposure -- but takes 6 weeks to be truly 100% conclusive.

2) No, an RNA test is not warranted in such a low risk situation.

Stay mellow while you await your additional test result(s). You can count on negative results.

I hope this information has been helpful. Let me know if anything isn't clear.

HHH, MD

I was doing research on the Alere Determine Ab/Ag test, and some research stated that most p24 Antigen would be present in most cases [by 16-21 days]. I was hoping the test reliability would  be higher than 70% by 3 weeks.   :(

I do intend on using a 4th Generation HIV Ab/Ag test again via an online lab on Monday, July 10th. At this point, it would be 32 days since the encounter. The lab service allows me to order the test online, go in for blood draw, and get results via email 2-3 days later.  Since this is not a POC Rapid 4th Generation test, I wonder which 4th Generation they use? [Abbot??]  

Thanks again!

I don't know which test Quest labs usually offer in this situation, but you should be able to figure it out on their website; or give them a phone call. However, it probably doesn't matter much:  all of the non-rapid Ag-Ab tests perform similarly, consistent with my comments above.

1) Not moot at all. As I said, the negative result was ~70% dependable.

2) As my comments above imply, you really didn't need testing at all after this exposure. However, now that you have started down that path, it makes sense for you to have a final, conclusive test. But why 4.5 weeks? Why not wait 10 days longer and have a truly conclusive test at 6 weeks?

3) As I also said above, it really doesn't matter what 4th generation test you have. All the lab based (non-POC) 4th generation tests are equally reliable (and 100% conclusive) 6 weeks after the last possible exposure. Whichever test Quest normally offers will be fine.