I had an oral exposure 31-32 days ago. The male (23 y/o) I gave oral sex to is a straight male who has never engaged in anal sex with anyone, and has not engaged in IV drug usage (as far as I know.) 

This oral experience was only for 2-4 minutes at max. There was no full ejaculation, but some pre-cum may have been present.

At 31 days from this exposure, I got a HIV fourth generation Ab/Ag test which came back negative. 

Given that this is an oral exposure, with a low risk partner, and a negative test at 31 days, should I regard this exposure as conclusive and be confident with my negative? Or should I retest at 42 days? Testing gives me a lot of anxiety so I would prefer not to.

Thanks so much.

Probably it makes no important difference, but I think you're female, right? The username you posted is one that can go either way!

Performing oral sex on a male is extremely low risk for HIV. Even if your partner had HIV, the CDC calculation is that there was one chance in 10,000 of you catching it. That's equivalent to giving BJs to infected men once daily for 27 years before transmission of the virus might be expected. Without ejaculation in your mouth, your risk probably was lower still. And you describe a partner who is exceedingly unlikely to have HIV. Had you asked before being tested for HIV, I would have said it wasn't necessary to be tested at all; for all practical purposes, there was no chance of HIV. As for the test itself, at one month the AgAb tests detect around 98% of infections. So if your risk started at, say, something like one in 10 million, with the negative result the possibility you have HIV would be around one chance in 500 million.

That said, technically the test wasn't conclusive -- 98% is good, but for 100% certainty the AgAb tests need to be negative 6+ weeks after the last possible exposure. As I said, if I were you, I wouldn't have felt a need to be tested at all, and I hope you'll agree that one chance in half a billion is zero. But you'll have to decide whether or not to test once more.

Other STIs are higher risk. The main one worth considering is a swab test for oral gonorrhea. And a syphilis blood test is more or less routine whenever any STI testing is done. But the chance your partner had either syphilis or gonorrhea also is near zero, so I'd probably let these go as well.

Since testing itself is anxiety producing for you, when the risk is this low you probably shouldn't test at all after any single exposure, especially if you choose partners as low risk as this one. If you have several such events a year, then once a year testing would make more sense than running to a clinic or lab after each event.

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

HHH, MD

My syphilis EIA assay was negative at 4 weeks/32 days from this exposure, I don’t think that is conclusive, however, so I will retest with an RPR in a few weeks. As for HIV, the chances are so low from this last exposure I think I’m just going to move on and stop convincing myself I have it.

Thank you so much once again. :)

In regard to syphilis testing, I initially got it done because there was a sore-like abrasion in my mouth on my inner cheek. I first felt it with my tongue about 10 minutes after eating a burning hot crab rangoon, that was so hot i couldn’t even keep my mouth closed. Following this event, I looked in the mirror to see this abrasion, and my mucosal tissue was coming off. Underneath, was redness, and obvious damage to my mouth. Initially, because I’m a hypochondriac, I thought of syphilis. I went to get tested the next day with the EIA (32 days post oral exposure) , and tested negative. TWO days after the abrasion/sore came up, it was basically completely healed, which leads me to think the sore was a burn instead of a syphilitic sore. Unfortunately, the timing matches up with a syphilis sore being present (4 weeks), but should I have any hope for my EIA to be accurate? I plan to retest at 12 weeks to fully be conclusive, but how should I feel about my experience? Thank you so much!!!

For background information purposes, I am a 20 year old female, non-drug user, have had one vaginal partner and 2 different oral partners, my last oral exposure was very short, with someone I am friends with, has only had sex with women, and does not use drugs. In addition, when I was performing oral, I saw no lesions or ulcers but it was in a low-lit area. I felt nothing with my mouth or tongue, and he’s said he has never seen anything on his penis to give him an idea of syphilis.  

Your exposure was virtually zero risk for syphilis, and an "abrasion" in the mouth is not suggestive of a syphilitic chancre. Almost certainly it is a coincidence and unrelated to the sexual exposure. Your EIA at 1 month was around 90-95% reliable, and you definitely can expect a repeat syphilis blood test to remain negative. It is exceedingly unlikely you have syphilis, and need not avoid having sex with new partners until you are tested.

I will delete your new question and ask the forum administrator to refund that posting fee. (With the three day weekend, that probably won't happen until Tuesday.)

But, your answer just gave me so much confidence and reassurance. I was looking for syphilis EIA accuracy everywhere. Thank you immensely and thank you as well for filing for the refund. 

Have a wonderful weekend and happy Labor day! 

In any case, this has gone a step beyond the usual two follow-up exchanges and so ends this thread. Stay relaxed as you wait for another syphilis test. It will be negative.

Best wishes and stay safe.