P24 Antigen + Antibody test

[rubberball314]

hi

All this info is upto date and is from the UK leading HIV source

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.

28day onwards up to 90 days testing that produces a negative is 99.98% accurate.....

And the result doesnt change after that the 28 days it remains negative as long as there is no further exposure during that time.

The Uk is reviewing the conclusive time which is set at 12 weeks this is purley for license and manufacture issues

[Sharkboy67]

Thank you for your reply. That would be good news. All the best.

[Vance2335]

I believe he might. We have always gone by the FDA, CDC and test manufacture recommendations.

[Sharkboy67]

Hi Vance, I see from your older posts you have changed your opinion; concerning the 4th Gen Duo (as has Nursegirl). Do you think the same would go for Teak.

[Vance2335]

Teak is actually helping on another website currently.

[Sharkboy67]

Perhaps I should have said the CDC have since June 2014; updated their guidelines concerning the 4th Gen Duo.

[Sharkboy67]

I have just looked at the webpages you have put on your post. This is old information. In fact if you read it. It only mentions the antibody test. It doesn't, mention the Duo test at all! It is true for antibody test it is 3 months. It also says ad for window period it depends on which test you use. Since June 2014 CDC have changed their guidelines concerning the Duo. Your webpage was clearly written before this. If Duo is negative after 28 days (and they clearly say Duo picks up infection quicker than antibody alone test). You do not have to retest again. Guess we will have to agree to disagree.

[morgan896]

The CDC have not changed their guidelines on window periods. It may be considered overly conservative by most experts, but 3 months is still what they advise to be absolutely certain.

http://www.cdc.gov/hiv/basics/testing.html

[Sharkboy67]

Why is there little word from Teak since CDC changed guidelines?

[Teak]

You're information is incorrect.

UK testing guidelines.
Post-test discussion

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.

http://www.bhiva.org/documents/Guidelines/Testing/GlinesHIVTest08.pdf