38 days exposure

[jasonjacobson]

Hello,
I Had unprotected sex with a female (regular girl, not sex worker) and about a week and a half later developed sore throat, swollen lymph nodes in neck, fatigue, aching muscles. I went to the doc and got antibiotics which slowly cured the throat and nodes but the fatigue has lingered for over a month.
I was tested for HIV antibody's 37 days after exposure and it was negative. This was a rapid test so am a bit confused as it states on the certificate that its ( Determine HIV-1/2 Ag/Ab Combo) but was told that it was only good for exposure up to 3 months ago.
The following day (38 days after exposure) I had another test done at a different office (HIV-1/2 AK/HIV-1 AG) which also tested negative.
1) Can you explain to me why the first test they stated 3 months?
2) These tests don't seem to test for antigen for HIV-2. Can you confirm this?
3) Being that 28 days is the general rule for antigen/antibody tests, do I need to consider having another test done?
4) Is there a difference between these 2 tests?
Thanks.

[Edward W Hook, MD]

Your information that antigen is detectable only one week before antibodies is incorrect, either out of date, out of context, or just plain wrong.  Antigen=virus and either antigen or antibody will be detectable in all persons with recently acquired HIV within 4 weeks of infection.

This will complete this thread.  EWH

[jasonjacobson]

Hello Dr. Hook,

My apologies if the content of my previous message came off as sounding argumentative as that was not my intention. I simply was questioning a lack of understanding on my part. As mentioned in many other threads, you state that, "Antibody only tests are conclusive at 8 weeks following exposure." And that antibody/antigen combo tests are conclusive at 28 days- to paraphrase.
I understand that the antibody test detects ONLY antibodies, and that the Duo test detects EITHER P24 antigen or antibody, dependant on whether antibodies have yet developed, or the protein antigen has developed prior to antibodies.
I do not understand why it has been stated that either the antigen of antibodies will appear with 28 days for the combo test for a definitive result, yet it is 8 weeks for a definitive antibody result. Why with antibody only test would it take 8 weeks for antibodies to be present, when it has been stated that it is likely antibodies will have developed within the 28 year period of Duo test? If it takes 8 weeks for Antibody tests to be definitive, and the protein antigen develops on average ONE WEEK prior to antibody development, why is there such a gap between the two definitive periods? This is what I cannot make sense of. Is the one week prior development of antigen to antibody not correct.
With 99.8% certainty the antigen shows up within 28 days for Duo is what you are stating correct? Then why not 5 weeks for antibody if antigen shows up no later than 28 days?
Thanks in advance for clarification. I do not wish to take up any more or your time than absolutely necessary, however I need to have a complete understanding of this for my own well being. Thanks again.

[Edward W Hook, MD]

I cannot tell if you are being argumentative or if You are misinformed.  The Duo tests detect the high concentrations of virus that are present before antibodies are detectable.  In virtually all persons who acquired HIV, by four weeks after exposure one or the other will be detectable.  EWH

[jasonjacobson]

Hello Doctor,

Thanks for your response. So I am assuming from your response that since 2010, theory of diagnosis timelines (or your opinion of these timelines) have changed. I am still somewhat confused as to why if the Duo test only shortens the time for detection by approx. one week (due to antigen detection prior to antibody development), why you state conclusive Duo test is 4 weeks, and yet conclusive antibody test is 8 weeks..there is a 4 week gap here. If you could please provide an explanation for this in a logical framework I will require no further assistance.
I appreciate your time and look forward to your response.

[Edward W Hook, MD]

You are reading older posts.  DUO tests are considered conclusive at 4 weeks as stated above.  EWH

[jasonjacobson]

Hello Doctors,

I have not yet had word back from you and am eager to hear your response as I am considering going back for another test (9 weeks post exposure). Thanks for your time.

[jasonjacobson]

Hello Doctor,

It's been several weeks since now since I last posted but wanted to go a bit further with this as there is some concern. I have had unexplainable swollen occipital lymph nodes for almost 2 months now so I came back to review some posts. I noticed that on a thread from 2010 you stated that Duo tests are about '90% accurate at 4 weeks.' This has given some new concern as in your last message to me you insinuate that the possibility of Duo test not picking up antigen or antibody at 37 days "does not mess with what we know about the biology of HIV." Can you please clarify for me as to why if there is  still a 10% change, it does not mesh with HIV biology that antigen/antibody could be not yet detected?

You mention that at 8 weeks, the duo test picks up the "presence or absence of HIV infection in virtually everyone." Being that the p24 antigen is detectable about a week prior to antibodies development, wouldn't it be logically prudent to have another Duo test at 7 weeks to be sure?

I realize that you base much of your estimation on risk level, however it is difficult to move on completely when there are still questions of concern.

Thanks for your time and I look forward to your responses.

[Edward W Hook, MD]

Your question about there not being enough antigen or antibody at 37 days does not mesh with what we know about the biology of HIV.  I repeat, a final time, you need to believe your test results.  You did not get HIV.  

If "everywhere you read about HIV" is the internet, then you are being foolish.  EWH

[jasonjacobson]

Thanks for your feedback. I'm still a little hesitant. Can you please respond to my question regarding possibility of not enough antigen yet in blood stream at 37 and 38 days to be detected? Is that at all possible? It's hard to feel ok about all of this when everywhere I read and every other doctor that I speak with says that 28 days is not sufficient time.
Your final comments and answers would be appreciated.
Thanks.

[Edward W Hook, MD]

No change in my assessment of advice.  HIV-2 is not a realistic concern and your tests would have detected antibodies to HIV-2.  No need for further testing.  EWH

[jasonjacobson]

Also, forgot to ask- since I was tested post symptoms with negative tests should that be an indication of anything?
Is it at all possible that there was not enough antigen yet in my blood samples to be detectable at 37 and 38 days?
I feel terribly unwell and run down but I know that this could be anxiety related to the stress of the past weeks.
I look forward to hearing back from you. Thanks for your time.

[jasonjacobson]

Thanks for this.
So despite the percentage for HIV-2, you still suggest no further testing? Is HIV-2 that rare in western North America?
My symptoms started approx. 12 days after exposure and lingered for around 2 weeks until throat/node symptoms were dealt with by antibiotics. As I mentioned the fatigue/general unwell feelings have not gone away still.
Are you still with the same advise that I have nothing to worry about due to both 37 and 38 day negative tests? These would have likely shown some response if I had something to worry about?
Hoping to be able to move on and not think about this any further but would like to hear back from you with final advise.
Thanks

[Edward W Hook, MD]

Welcome to our Forum.  I'll be pleased to comment. Your question is a frequent one.  The exposure you describe was very low risk for HIV (somewhat higher for other STIs, I suggest that if you are worried about HIV, you should also be tested at least for gonorrhea and chlamydia) since HIV is a rare disease among heterosexual women and the risk for infection in the unlikely circumstance that your partner was infected is less than 1 infection per 1,000 exposures, on average.  The flu-like illness you experienced occurred a bit early for the symptoms of recently acquired HIV and multiple studies have shown that very few persons with flu-like illness have HIV, most of such illnesses being caused by other, non-STI sorts of virus that most people will get from time to time.  

1) Can you explain to me why the first test they stated 3 months?

The traditional and most widely used tests for HIV are tests for antibodies to HIV which are available both as so-called "rapid" or point of care tests which can be done in the clinic and laboratory based antibody tests. For all practical purposes both of these types of test perform comparably and provide accurate information on the presence or absence of HIV infection in virtually everyone at 8 weeks following exposure.  More recently, combination tests for HIV antibody AND the HIV p24 antigen such as both of the tests you had have become available which reliably detect infection by the end of 4 weeks after exposure.  The recommendations for testing at 3 and even 6 months are the result of two factors- data from older tests no longer used (you really do not need to worry about which generation of tests you were tested with, at this time virtually all tests are far more sensitive that they were even 2-3 years ago when the 3 month recommendation was made) and secondly, the fact that some, mostly governmental agencies which have to provide recommendations for virtually everyone without the sort of interactions such as those you get with your doctor or on personalized sites such as this one, feel they cannot "afford" to be wrong and therefore make recommendations and guidelines which leave most people unnecessarily nervous for weeks longer than the it takes virtually everyone to develop HIV antibodies.
  
2) These tests don't seem to test for antigen for HIV-2. Can you confirm this?

Correct, they do not detect the HIV-2 antigen however, HIV-2 is far rarer than HIV-1.  The test you have had would have detected antibodies in well over 90% of recent HIV-2 infections.  My advice would be to believe your test results.  

3) Being that 28 days is the general rule for antigen/antibody tests, do I need to consider having another test done?

I see no reason for further testing. Your exposure was low risk, your symptoms began a bit soon to reflect recently acquired HIV and you have negative tests.

4) Is there a difference between these 2 tests?
Not in terms of performance. They are held to similar performance standards by regulatory agencies.

My advice would be to not worry further about this exposure and to move forward without concern.  EWH