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Help P24 test advise needed
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Help P24 test advise needed

I had a HIV P24 Duo test in Hong Kong 16 days after sex. The sex was MSM but I slide my penis into my partners anus for about 1 sec and also my male partner came a little in my mouth. But apart from these we used condoms. 9 days after sex I got some diarrhea for a few days and a rash on my chest and a sore throat. I had no high temp or fever.

I went to a STD clinic here and they did the P24 test on day 16 and it was negative. Do you think I can be sure this result is accurate ?  I read that P24 becomes detectable after 10 days and peaks at 16 days.  So can I take this to mean my negative test at day 16 is good news ?

I am just worried as although the diarrhea only last 3 days, I still have a sore throat (not very sore, just a little) and a slight red rash on my chest around the colar bone.  My anxiety levels have shot up, and I can't sleep from worrying.  The STD centre I did the P24 Duo test said I should be fine, and I read online the manufacturer of this test says it can detect P24 after 5 days, but they say after 14 days its certain to detect P24 if I was exposed.

I am thinking should I get a RNA PCR test ?  But I think these cost a lot more and I am not sure if they offer them in HK.  Anyway advice is much appreciated.  I have also asked the guy I had sex with (who said he is hiv neg and tested last year) to take a test himself later today to put my mind at rest.  Many Thanks.
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Avatar_m_tn
You clearly state in your post that you had a DUO test on day 16. A DUO test includes an antibody test, as explained by Dr Gonzalez-Garcia on this very web site:

"- HIV 1 and 2 antibodies and p24 antigen test (HIV DUO or HIV Combi test)

This HIV test is licensed in the EU for use after 28 days after a possible exposure. It is probably much better than this and will probably identify the majority of newly infected HIV positive individuals at between 14 and 21 days. This HIV test is referred to as a fourth generation HIV test. Certainly in our clinic we have had many new diagnoses of patients using this HIV DUO test combination in that time frame.

The HIV DUO test relies on the principle that when HIV first establishes itself in the body it will start to replicate rapidly and almost as a by-product of this replication a core protein - the HIV p24 antigen - is produced in huge amounts from around 10 days or so after first infection and before or during the time when antibodies to HIV are being formed. The p24 antigen will then stay at a very high level for the first few months after infection and later decline in line with the decline in HIV viral load as referred to above. It will though never completely disappear and will run a variable course of detection through the rest of the illness.

So in general, p24 antigen is formed slightly before antibodies are forming allowing us to close the gap between infection to detection time - the HIV window period. As time goes on, then the majority of newly infected HIV positive people will form antibodies to HIV 1 or 2 by 28 days. In combination then, looking for both the HIV 1 p24 antigen and also HIV 1 and 2 antibodies will allow for much earlier detection of HIV than looking for HIV antibodies alone."

All of that said, whilst DUO tests do not have to be followed up by antibody tests the timing of your test was too early to be conclusive (although it is highly encouraging). The worry with RNA PCR tests is false positives, the doctors on the paid forum only recommend them for high risk exposures. Dr Handsfield's advice here may be of assistance:

"The time to a positive HIV test (the seroconversion window) has been discussed many times on this forum.  But since we don't yet have an FAQ section, the information can be a little hard to find, so it bears repeating from time to time.  Here it is again.

The tests are the same everywhere.  There is no rigid window period.  As time goes on, more and more infected people have positive tests.  The available data are not preciese, but according to most experts around 50% are positive by 2 weeks, 90% by 4 weeks, 95+% by 6 weeks, 99% by 8 weeks, and three months is the longest it ever takes.  Doctors and health departments that advises testing at 6 months are being overly and unnecessarily conservative.

On this forum, our replies about when to test do not depend only on the test reliaibility, but on the overall context.  If someone has only 1 chance in 100,000 of having caught HIV, a negative test at 4 weeks (90% reliability) drops those odds to 1 in a million.  That's close enough to zero that such a person doesn't really need additional testing, except for psychological reassurance.  On the other hand, if the exposure was high risk and the odds s/he caught HIV are, say, 1% (1 in 100) a 4 week test drops that chance to 1 in 1,000.  That's helpful, but not good enough.  That person needs testing at 6-8 weeks and perhaps 3 months.  Same test but different situations, therefore different testing advice.

All this is for the standard HIV antibody tests.  The certainty of a negative result often can be increased by adding a test for the virus itself, like p41 antigen (included in the Duo test) or PCR to detect viral RNA.  If one of these plus an antibody test is negative at 4 weeks, that's essentially 100% proof the person didn't catch HIV.  However, PCR testing can give false positive results, which of course can be very frightening -- so it usually isn't recommended expcept in especially high risk situations." (Source: http://www.medhelp.org/posts/HIV-Prevention/HIV-Testing-/show/764623)

You could have another DUO test at 28 days, this might be useful in that regard: http://www.medhelp.org/posts/HIV-Prevention/-A-Question-on-Testing/show/1347755 , and then if needs be a final 'belt and braces' test at 3 months to absolutely put your mind at rest if needs be.

Re symptoms: you will read repeatedly on here, and elsewhere, that HIV is never diagnosed by symptoms, some people have no symptoms at all of course, and in those that do the symptoms of initial infection are non-specific, and the same as those that can be caused by innumerable other ailments, many commonplace and not serious. Hold onto this. By the time I had gone through my anxiety I had experienced pretty much every symptom I had ever heard of being associated with ARS (so many I think I even started moving onto full blown AIDS). Do yourself a favour and do not read up on symptoms. Anxiety can create most of them, including weakening your immune system so that you catch minor ailments which your imagination will gladly jump all over and amplify.

Your symptoms were rather early to suggest HIV, and the lack of a fever is often cited as further evidence against. From what I have read the rash is usually body wide, not localised as in your example, and the sore throat would usually be expected to be rather severe.

From your post it would seem that everything is pointing to the fact that you were not infected, and that your test was extremely encouraging news, try and keep all of this in mind until time has past enough for you to obtain definitive reassurance, and not let your worry get out of proportion.
Related Discussions
17 Comments Post a Comment
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Avatar_m_tn
P24 tests are supplemental tests that have to be followed up with an antibody test.
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Avatar_m_tn
Thanks Teak, but can I take any comfort or be hopeful at the result of the P24 test ?  Do you think taking the RNA PCR test at day 18 would be more conclusive ?
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Avatar_m_tn
You clearly state in your post that you had a DUO test on day 16. A DUO test includes an antibody test, as explained by Dr Gonzalez-Garcia on this very web site:

"- HIV 1 and 2 antibodies and p24 antigen test (HIV DUO or HIV Combi test)

This HIV test is licensed in the EU for use after 28 days after a possible exposure. It is probably much better than this and will probably identify the majority of newly infected HIV positive individuals at between 14 and 21 days. This HIV test is referred to as a fourth generation HIV test. Certainly in our clinic we have had many new diagnoses of patients using this HIV DUO test combination in that time frame.

The HIV DUO test relies on the principle that when HIV first establishes itself in the body it will start to replicate rapidly and almost as a by-product of this replication a core protein - the HIV p24 antigen - is produced in huge amounts from around 10 days or so after first infection and before or during the time when antibodies to HIV are being formed. The p24 antigen will then stay at a very high level for the first few months after infection and later decline in line with the decline in HIV viral load as referred to above. It will though never completely disappear and will run a variable course of detection through the rest of the illness.

So in general, p24 antigen is formed slightly before antibodies are forming allowing us to close the gap between infection to detection time - the HIV window period. As time goes on, then the majority of newly infected HIV positive people will form antibodies to HIV 1 or 2 by 28 days. In combination then, looking for both the HIV 1 p24 antigen and also HIV 1 and 2 antibodies will allow for much earlier detection of HIV than looking for HIV antibodies alone."

All of that said, whilst DUO tests do not have to be followed up by antibody tests the timing of your test was too early to be conclusive (although it is highly encouraging). The worry with RNA PCR tests is false positives, the doctors on the paid forum only recommend them for high risk exposures. Dr Handsfield's advice here may be of assistance:

"The time to a positive HIV test (the seroconversion window) has been discussed many times on this forum.  But since we don't yet have an FAQ section, the information can be a little hard to find, so it bears repeating from time to time.  Here it is again.

The tests are the same everywhere.  There is no rigid window period.  As time goes on, more and more infected people have positive tests.  The available data are not preciese, but according to most experts around 50% are positive by 2 weeks, 90% by 4 weeks, 95+% by 6 weeks, 99% by 8 weeks, and three months is the longest it ever takes.  Doctors and health departments that advises testing at 6 months are being overly and unnecessarily conservative.

On this forum, our replies about when to test do not depend only on the test reliaibility, but on the overall context.  If someone has only 1 chance in 100,000 of having caught HIV, a negative test at 4 weeks (90% reliability) drops those odds to 1 in a million.  That's close enough to zero that such a person doesn't really need additional testing, except for psychological reassurance.  On the other hand, if the exposure was high risk and the odds s/he caught HIV are, say, 1% (1 in 100) a 4 week test drops that chance to 1 in 1,000.  That's helpful, but not good enough.  That person needs testing at 6-8 weeks and perhaps 3 months.  Same test but different situations, therefore different testing advice.

All this is for the standard HIV antibody tests.  The certainty of a negative result often can be increased by adding a test for the virus itself, like p41 antigen (included in the Duo test) or PCR to detect viral RNA.  If one of these plus an antibody test is negative at 4 weeks, that's essentially 100% proof the person didn't catch HIV.  However, PCR testing can give false positive results, which of course can be very frightening -- so it usually isn't recommended expcept in especially high risk situations." (Source: http://www.medhelp.org/posts/HIV-Prevention/HIV-Testing-/show/764623)

You could have another DUO test at 28 days, this might be useful in that regard: http://www.medhelp.org/posts/HIV-Prevention/-A-Question-on-Testing/show/1347755 , and then if needs be a final 'belt and braces' test at 3 months to absolutely put your mind at rest if needs be.

Re symptoms: you will read repeatedly on here, and elsewhere, that HIV is never diagnosed by symptoms, some people have no symptoms at all of course, and in those that do the symptoms of initial infection are non-specific, and the same as those that can be caused by innumerable other ailments, many commonplace and not serious. Hold onto this. By the time I had gone through my anxiety I had experienced pretty much every symptom I had ever heard of being associated with ARS (so many I think I even started moving onto full blown AIDS). Do yourself a favour and do not read up on symptoms. Anxiety can create most of them, including weakening your immune system so that you catch minor ailments which your imagination will gladly jump all over and amplify.

Your symptoms were rather early to suggest HIV, and the lack of a fever is often cited as further evidence against. From what I have read the rash is usually body wide, not localised as in your example, and the sore throat would usually be expected to be rather severe.

From your post it would seem that everything is pointing to the fact that you were not infected, and that your test was extremely encouraging news, try and keep all of this in mind until time has past enough for you to obtain definitive reassurance, and not let your worry get out of proportion.
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Avatar_m_tn
Dear Vworried005,

I am so very grateful you took the time to write that reply to me, it is a huge help. I am profoundly grateful.  I do think my anxiety levels are off the scale and causing my headache and nausea.  Yes I will stop looking online at symptoms etc as I know this is not helping me.

I will follow your advice, try not to panic and get a second p24 duo test at 28 days, and once more at three months.

Thanks again....
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Avatar_m_tn
UK Testing Guidelines

http://www.bhiva.org/documents/Guidelines/Testing/GlinesHIVTest08.pdf
Post testing
Page 11
The need for a repeat HIV test if still within the window period after a specific exposure should be discussed. Although fourth generation tests shorten the time from exposure to seroconversion a repeat test at three months is still recommended to definitively exclude HIV infection.
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Avatar_m_tn
Is there any logic to my rash, is maybe is more related to the heat and sweat of Hong Kong in sunlight with a Accuweather real feal today of 43 degrees celcius.  As I had the rash 4 days before the p24 test, I have been told elsewhere it would be unusual to get a rash so soon, ie  12 days after a possible exposure.  But if it were a rash caused by HIV seroconversion (which I had for 4 days before the test) would that lend any weight to the body having produced enough reaction to the virus to triggered the P24 test ?

Also by applying some betamethasone dipropionate topical solution to the area around my neck and colar bone (bought from the chemist) to treat  skin inflammation Indications: Suppression of skin diseases in which inflammation is a prominent feature, e.g., eczema, atopic dermatitis, dermatitis herpetiformis, contact dermatitis, dermatitis venenata, seborrhoeic dermatitis, neurodermatitis, psoriasis and intertrigo. The rash is going away, so again is this a good sign ?
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Avatar_m_tn
Get your conclusive test result and you'll know your status.
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Avatar_m_tn
Teak, in another post you reproved me for my mentioning my profession. I did so there in the same context raised by your reply here, namely that I recognise the reasons why the bodies cited must stick to conservative recommendations with regards testing windows. I also appreciate why you stick doggedly to that advice, and given your influence why this forum agrees with that position.

However, to london28uk, this is not the only opinion out there. I would urge you to conduct even a cursory glance over the paid side of this forum, and the International forum, where you will find all of the doctors, without exception, take the same line that you can rely on the DUO test sooner than 3months. In fact please do read a few posts on the International forum.

I have taken the liberty of finding some of the more recent ones for you:
http://www.medhelp.org/posts/HIV---International/negative-duo-test-at-40-days-reliable/show/1466195
http://www.medhelp.org/posts/HIV---International/4th-Generation-test-at-35-days-/show/1489472
http://www.medhelp.org/posts/HIV---International/Is-my-test-conclusive/show/1461993
http://www.medhelp.org/posts/HIV---International/CAN-I-STOP-WORRING/show/1416802
http://www.medhelp.org/posts/HIV---International/HIV-DUO-TEST-/show/1422102
http://www.medhelp.org/posts/HIV---International/HIV-antibody-and-p24-antigen-test-at-week-12-definitely-conclusive/show/1410816
http://www.medhelp.org/posts/HIV---International/4th-Generation-Test-at-6-weeks/show/1410930
There are loads more along the same lines.

The doctors on that forum are all eminent and experienced members of one of the most renowned and used private clinics specialising in this in Harley Street. I think their responses would be helpful to you regarding DUO testing at 28 days +. It is of course up to you what you believe, and what brings peace of mind, regarding the testing window. Personally given the extensive rationales expounded by all of the doctors on the forums listed, as well as that of my own testing doctor in Bristol who also has years of first-hand experience in this, I know which side of the fence I fall on. I hope this helps you come to an informed decision either way, I am not trying to influence you, merely present the argument for your information.

Please stop stressing about your rash, it far more likely that it is caused by any number of possible things not remotely sinister (maybe even stress/anxiety itself), and it does not sound like the rash associated with ARS anyway. Rashes are very common anyway, you probably have them more than you realise, just aren't in this heightened state of awareness and so let them go without much thought. Worrying about symptoms is fruitless in this context, and may even make them worse. I know it is hard to detach yourself in this way but you must try. Maybe consider relaxation techniques (many available for free online) to give you some respite for now, they helped me.  
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Avatar_m_tn
* Anyone who continues to post excessively, questioning a conclusively negative result or no-risk situation, will be subject to action by MedHelp. Conclusively negative results or a no-risk situation will be based upon the criteria established by MedHelp’s doctors. Action will be taken as follows:
    * After excessive posting, a warning will be issued by MedHelp
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Avatar_m_tn
None of those points are relevant to my response, why did you post it?
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Avatar_m_tn
Vworried005, Just wanted to thank you again, I am now reading the posts you listed. Its weird leaving my friends and family in the UK and dealing with this alone in Hong Kong. So I really appreciate your posts to me.
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Avatar_m_tn
I know that feeling well. I was in Asia away from home, friends, and family when I had my 'problem', and sometimes forums like this are all you've got to try and work out what you should do. There is an HIV anxiety forum on here which you might find useful. Many people have been here before you, there is a wealth of information on these forums already.
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Avatar_m_tn
Testing
http://www.cdc.gov/globalaids/Resources/pmtct-care/docs/TM/Module_6TM.pdf

page 11
number 4

A negative result usually means that the person is not infected with HIV. In rare period.” This is the period of time between the onset of infection with HIV and the appearance of detectable antibodies to the virus. The window period lasts for 4 to 6 weeks but occasionally up to 3 months after HIV exposure. Persons at high risk who initially test negative should be retested 3 months after exposure to confirm results.
http://www.fda.gov/downloads/BiologicsBloodVaccines/BloodBloodProducts/ApprovedProducts/LicensedProductsBLAs/BloodDonorScreening/InfectiousDisease/UCM216314.pdf
Page 27
An ARCHITECT HIV Ag/Ab Combo test result that is nonreactive does not exclude the possibility of exposure to or infection with HIV-1 and/or HIV-2. Nonreactive results in this assay for individuals with prior exposure to HIV-1 and/or HIV-2 may be due to antigen and antibody levels below the limit of detection of this assay.

UK Testing Guidelines

http://www.bhiva.org/documents/Guidelines/Testing/GlinesHIVTest08.pdf
Post testing
Page 11
The need for a repeat HIV test if still within the window period after a specific exposure should be discussed. Although fourth generation tests shorten the time from exposure to seroconversion a repeat test at three months is still recommended to definitively exclude HIV infection.
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Avatar_m_tn
Would that be the same CDC and BHIVA that state there is a risk of acquiring HIV through oral sex (and yes, I did just check both) when you categorically state, repeatedly, there is no risk from any form of that activity? I am not raising that to start yet another debate on that particular issue, merely to ask why you feel it is acceptable to pick and choose when these guidelines apply.
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Avatar_m_tn
CDC and BHIVA are not the parties that approve HIV tests nor can they make changes nor can any doctor make changes without exposing themselves to lawsuits. Had you had any knowledge of HIV you would know that the CDC was one of the principle parties in the study on oral sex.
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Avatar_m_tn
That does not answer the question. Neither does it take you any further forward really in justifying your position regarding testing windows. It merely reconfirms what has been said.

I appreciate you putting the original quoted information there though, it can only be a good thing to present as much information as possible. I wonder if we're going around in circles and it is time to let the various 'advices' speak for themselves.

I didn't come here to argue with you Teak, I merely presented prior relevant responses from other (medically trained) sources to the question asked. That their views differ from yours on this one is simply the way it is. As you assert, and I have said more than once, it is not my place to say which is correct. I do feel it may be an insult to other users if we continue in this vain; they are worthy of using the information presented on both sides to its best effect I am sure. I just felt it was important that they had the opportunity.
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Avatar_m_tn
Correct, now move along.
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