[Question #3081] How soon is P24 detectable?--Dr. Handsfield please

39 months ago
Hello..I had a risky exposure going on almost three weeks ago now.  The exposure was brief sex but SO worried about the encounter.  I have had no rash, or fever.
1) I have read LOTS about the variable tests available and was wondering what is the level of accuracy that a HIV duo test would show at 3 weeks post exposure?  
2) How accurate would a duo test be at 3 weeks?
3) What is the peak of p24?
4) Am i wasting my money on it at 3 weeks of will it give me a good indicator?
Thank you
H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
39 months ago
Welcome back to the forum, but sorry to see you found it necessary.

In order to properly respond, it would be helpful to know more about the exposure you are concerned about. Heterosexual? Vaginal, anal, or oral sex? Condom protected? If heterosexual with a partner not known to have HIV, then it was a low risk event. In the meantime, directly to your questions:

1,2) These are the same question in different words. Around 80-90% of newly infected persons would have positive results with the antigen-antibody (duo) test at 3 weeks.

3) I'm not sure what you mean by "peak of p24". The large majority of infected people would have detectable p24 antigen in blood by 3 weeks.

4) Whether it was a "waste of money" to be tested at 3 weeks depends a lot on the nature of the exposure. As implied above, if the exposure was truly high risk, the negative result should be highly reassuring, although not conclusive.

I hope these comments are helpful. I'll be happy to comment further if you'd like to fill in the details ofthe exposure. But in the meantime, it seems unlikely you have HIV.

39 months ago
The exposure was protected vaginal sex with a female sex worker.  There was no oral.  On the other hand while we were having sex, she put her finger in my ass for a minute or two and gave me a prostate massage.  She did not use any sort of finger cot.  After the whole episode I asked her if she had any diseases and she said no. (possibly politically correct answer) What puts my mind on edge is if she could have infected me somehow by fingering me.  I do have some internal hemorroids and if she had a small cut /bleed or something there could have been fluid exchange therefore leading to the risk of infection.  I want to test asap
1) What test could I take at this time and how reliable would it be?
2)If i took the duo test now, are you saying it is 80% reliable?
3)When would p24 be at the highest levels?
4)I am just nauseated thinking about this whole event, how much risk did I put myself in?  Protected sex, but the 'other'
5)I am a married man and didnt think about others, how worried should i be about sexual relationships with my wife?
6)should i be on the lookout for ARS?  I havent had any swellling, fever, rash, etc

Thank you
H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
39 months ago
Thanks for the additional information. All in all you are at little risk of HIV and there is almost no chance you were infected. First, in the US, under 1% of female sex workers have HIV. Second, if she had it, the average risk of transmission through a single episode of UNprotected vaginal sex is 1 chance in 2,500. And condoms are about 99% effective. Therefore, the mathematical chance you caught HIV is 0.01 x 0.0004 x 0.01 = 0.00000004. That's 4 in a hundred million, or 1 chance in 25 million. And that's even before you were tested. If you have a duo test at 3 weeks, with 80% reliability, the odds you have HIV will drop to roughly 1 chance in a hundred million.

The tone of your thoughs reveals continuing panic. As these numbers suggest, that is irrational and unwarranted. And once again almost all these questions are different versions of the same question.

1) Wait until the 4 week mark and have a duo (antigen-antibody) test, at which time it will be nearly 100% conclusive. (6 weeks for truly conclusive.)
2) Repeat question:  I already said 80-90% reliable.
3) p24 itself doesn't matter;  you apparently don't understand the test, which detects both p24 antigen and antibody.
4) This is an irrational panic reaction. Settle down.
5) You can safely have sex with your wife now, without waiting for test results. That's what I would do if I were in your circumstance.
6) If you were going to have ARS symptoms, they would have started before now. You can assume you are home free.

Reallly, mellow out. You are seriously overreacting to a sexual decision you regret. Try to separate those feelings from disease risks from the decision: they aren't the same. Deal with the emotional stuff as you need to (maybe discuss with your wife?), but you can forget HIV. There is no realistic chance and you can expect any further tests to be negative.

Perhaps it will also help you to know that in the 14 years since I have been answering questions like this online, with thousands of question, not one person turned out to have caught HIV. You aren't going to be the first. If and when that happens, it will be from a truly high risk exposure and not a low risk event like yours.

Note the forum permits two follow-up comments for each question, so I suggest no further comments on this thread until you have a test result to report, preferably an antigen-antibody test at least 4 weeks after the exposure. I won't have any more comments or advice until then.

39 months ago
Thank you for the response and I do apologize but I need to get a few clarifications.  I will indeed post my results though if afforded the opportunity on this thread.  If not I will purchase another for that purpose.  The sexual act doesn't bother me at all as that was protected.  What does REALLY bother me is that she stuck her finger in my anus with out any sort of protection.  I cannot imagine this not being a risk in the event she had cuts or even a hangnail that had some blood on it and therefore possible fluid exchange.  I should have thought better!!!  I see that some experts say no risk and others say negligble.  Just really scares me.  I would like you to be BRUTALLY HONEST with me if you would, even if they aren't the answers i want to hear.  I need to for some peace of mind test at the three week mark, which will be on MONDAY(I will repeat at 6 weeks)and as said will post if you let me. To my questions
1)IF one isn't having symptoms of ARS(fever, rash, enlarged lymph nodes, sore throat), is that a good indicator?
2)IF p24 is at a high level at three-four weeks and then starts to decline, why would the antigen part not pick it up(false negative)?
3)Would an RNA test be a better test at three weeks?
4)IF you are in fact having symptoms of ARS and at that time get tested, does the test usually come back reactive?
5)My wife is having similar bloating and sore throat, but no rash or fever, should I be concerned for her?
6)How risky is the fingering aspect of my exposure?
7)As said, my only real symptom that I am having is prominent bloating, stomach upset and nausea.  I am hoping it is just nerves, can that alone be a HIV indication?

I REALLY want this to go away now but I know not possible until all testing is done.  I DO NOT want to be
A)first case documented to get HIV from fingering
B)your first case ever here where there was infact a bad outcome from the exposure.

I thank you for your time and again I will post results if afforded the opportunity
39 months ago
And to clarify on the first part of my last response, i do have internal hemorroids if that makes any difference.  Just thought you should know all of the history
H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
39 months ago
I saw and took the anal fingering part of your exposure into account. Fingering (anal or vaginal) is entirely risk free. It never transmits HIV or STDs.

You are serioiusly overthinking all this and you are finding statements in your excessive online searching that you don't understand or have misinterpreted.

1) Absence of symptoms by 2 weeks is reassuring, but only slightly.
2) This shows you don't understand the test and how it works. p24 continues to rise until antibody appears. It is the antibody that clears p24 from the blood. So when p24 declines, antibody must be present. The actual level of p24 doesn't matter and is not measured by the test.
3) No, RNA testing would not be any better.
4) Yes. The test is almost always positive if there are symptoms caused by ARS.
5,7) Neither your symptoms nor your wife's sound like HIV. Even if you were infected, it is too soon for her to have been infected and develop symptoms.
6) Zero, see above.

A and B) These things aren't going to happen.

That concludes the two follow-up comments and replies included with each question, and so ends this thread. I'm sorry you didn't accept my offer to comment once more after your test results were available. Please note the forum does not permit repeated questions on the same topic or exposure. This being your second, it will have to be your last; future new questions about this exposure, testing, and your fears about HIV, herpes, or other STDs will be deleted without reply and without refund of the posting fee. This policy is based on compassion, not criticism, and is designed to reduce temptations to keep paying for questions with obvious answers. In addition, continued answers tend to prolong users' anxieties. Finally, such questions have little educational value for other users, one of the forum's main purposes. Thank you for your understanding.