A doubt coming from reading here

HI,

I have read that P24 test is used after 3-4 weeks of the exposure to find the p24 antigen that is specific of HIV, but must be confirmed by an antibodies test.
I also have read that antobodies apears after 2 weeks and that elisa 4th generation can find them after 21 days.
My question is if ELISA 4th generation combines the searching for antibodies and the searching for p24 antigena and
if someone takes this test a the one month point, and is negtive. (no p24, no antibodies) can be sure that is conclusive??

[Teak]

NO.  http://jcm.asm.org/cgi/content/abstract/40/4/1420

[adfez]

I really didnt understand anything from that reading

[Teak]

The diagnostic window was reduced with VIDAS HIV DUO Ultra by 3.82 days, on average, in comparison with the fourth-generation assay with the lowest sensitivity of the antigen detection module. HIV-1 infection was detected 5.88 days earlier than with third-generation EIA.

And the window period for a standard ELISA test is 3 months. So no 21 days negative would not give you a conclusive negative result.

[derson_70]

Brazil has one of the best AIDS programs in the world today manufacture our own rapid tests with sensitivity of 100% certified by the CDC and FIOCRUZ. Two tests are performed in parallel, if both are negative diagnosis is closed in case of disagreement a third test is done if not, new sample collected after 30 days, if positive, closed for infection diagnosis. These tests have window of 60 days after contact. Two virologists laboratory site aidsportugal (Dr Ricardo Camacho and Dr Perpetua) says that almost 100% of infections occur in 45 dias.O NAT used in blood banks has window of 12 days, as they and not the virus antibodies. Tests of sensitivity is 4th after 3 weeks due to the p24 antigen, but each reacts differently, it is repeated after 60 days. Before speaking here, I find that reading about the trials in Brazil.

[Teak]

The only conclusive negative test is one obtain three months post exposure.

[derson_70]

A 4th generation test differs from a theory of 3rd only because the p24 antigen (strain of HIV-1) that appears once in the first weeks and then disappears, then appears in the symptomatic phase of disease, indicating the weakness of the immune system. The p24 immune so reduces the window, but after the period of seroconversion, whatever be the 3rd or 4th geração.Os current tests are very sensitive some countries such as Brazil and Portugal using a window of 8 weeks for completion of tests.

[derson_70]

Article go to the link below is in Portuguese use the google translator. Document of the Ministry of Health of Brazil and samite surveillance.

http://www.saude.rio.rj.gov.br/media/dstaids_consenso_2008_testagem.pdf

[Vance2335]

The standard by the CDC and makers of the antibody tests is 3 months. That is what is used here and recommended.