Fourth generation testing

[Probelmpaul]

Hi,

I would like to get your expert opinion regarding the window period of fourth generation HIV tests (those that test for antibodies & p24 antigen).

I searched the internet but I am a little confused/ surprised as different scientists and medical practitioners seem to have very different points of view. I also searched this forum – my apologies if my topic was discussed already.

While some sources say that the window period remains 6 weeks for fourth generation HIV test, there are others which claim that a majority of infections already show earlier, between 2-3 weeks due to the p24 reaction.
Also on the POZ site I read that the approximate time for fourth generation tests would be 3 weeks after possible exposure.

How reassuring or accurate do you consider a negative 4th generation antibodies & p24 antigen test for HIV-1 after 3 weeks (approximate probability to have a false negative result)?

Thanks 😊

[Jim Allen]

What was your risk?

[Probelmpaul]

Hi Jim,
the condom broke during insertive vaginal intercourse for a couple of minutes. So I am aware that there was a risk for hiv transmission.
The fourth generation test after 19 days came back negative but I am confused due to the different points of views regarding its validity.
I know that I have to repeat after 28 days (official UK guidelines) but would still like your opinion if a test after 19 days can be an indication of any kind.

[Jim Allen]

Hiya,

Firstly p24 is not infallible, its one of the reasons why its not used as standalone in screening.

Any approved 3rd or 4th generation HIV antibodies test "might" pick up on an infection as early as the 3rd week although it would be far from conclusive.

Test at 6 weeks post exposure for a result, this 6 weeks result will rarely ever change and, its up to you if you would wish to confirm the results at the 3 month mark.  Do remember to also test for far easier to acquire STI's whilst you are at it.

Best, Jim.

Here's what you need to know in order to avoid HIV infection:
Use condoms for anal or vaginal intercourse, correctly and consistently, every time, no exceptions. Consider starting PrEP as an additional layer of HIV protection going forward

Keep in mind that some sexual practices which may be described as safe in terms of HIV transmission might still pose a risk for acquiring far easier to transmit STI's, so please do get fully tested regularly and at least yearly for all STI's including but not limited to HIV and test more frequently if unprotected intercourse occurs

Also note that it is possible to have an STI and show no signs or symptoms and the only way of knowing is by testing.

More information on HIV Basics, PEP, TaSP and Transmission can be found through the links in my signature to our POZ pages, this includes information on HIV Testing

Please Note.
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[Probelmpaul]

Thanks, I appreciate it!
Until then I try to relax as good as I can :-)