Test positive within 2 w of onset of symptoms?

[scared692007]

Hi there, any comments about information that I found from As A doctor Forum. According to doctor (HHH) HIV test is always positive within two weeks of onset of symptoms (ARS): "The antibody tests almost always are positive within 4-6 weeks of exposure, and always positive within 2 weeks of onset of symptoms."

Is it regardless how long your ARS last (e.g. case prolong) or is based on statistics that most of the people has only 1-2 weeks ARS phase. Does anyone have any further information about this fact or hypothesis?

Original thread can be found under Title: antibodies and seroconversion illness.

Thanks in advance.

[Ausguy]

ARS is usually the cause of the immune systems reaction to the virus. Thus the antibodies should be produced during this stage. And thus, two weeks afterwards there should be enough detectable antibodies to return a positive test. I think he is counting from the onset of symptoms.

I think that is the basic idea of his hypothesis.

[regularjoey]

There was a published study a few years ago that demonstrated that the antibody tests turned positive 1-2 weeks after the onset of symptoms, so it's not just a hypothesis.  Ausguy gives the right reasoning for why does that happen.

[GOLOKA]

Does your CD 4 / CD 8 get inverted ?

[sunsarethebest]

this was posted by someone else before, read it. its good knowledge:

The question of windows period post-exposure is one of the most common ones on these boards.  I've spent some time doing investigation.  I am a scientist by trade, although not a biologist nor medical doctor.  

The first thing that struck me is the lack of recent studies to reaffirm the current guidelines of 13 weeks. Especially as tests have improved over time.  I've found only one well-written study and it is this one (published: 2000)
http://www.aidsonline.com/pt/re/aids/fulltext.00002030-200010200-00014.htm;jsessionid=GpvJP3Q2p2xvCGsVJg2yylpMDpM5nV62XVcl0zWMchp922jmlCKF!-756477024!181195629!8091!-1

What they did is used a series of blood draws from people that would turn out to be HIV infected, and ran them against a set of HIV tests.  They used modern tests of the time (1997) as well as data from tests in 1987.  A few interesting observations:

1) Of people they could pinpoint to a single exposure, they all showed symptoms in four weeks.  87% showed symptoms in first 15 days.  
2) The antibody tests in 1987 were a LOT less sensitive.  The most sensitive 1987 antibody test detected all positive samples by ~26 days after first *symptoms* appeared.  And the average 1987 antibody test was closer to ~36 days after first symptoms.  
If you add 15 (time for first symptoms) +36 this puts you to about 51 days post-exposure before there was high confidence that you could detect antibodies.  This probably explains the 13 week guidance.
3) The antibody tests in 1997 were much more sensitive!  Note, even first generation tests were drastically improved:
"By the 1987 Abbott first-generation test, employing cell-lysate antigens, 99% of seroconversions were estimated to occur within 48/78 (early/late) days. The improved 1997 Abbott first-generation test detected seroconversion significantly earlier with 99% estimated within 16/20 days."
The first generation tests removed 32/58 days from the window.  That's about a 5-8 week reduction!
4) The worst 1997 test detected antibodies at about 20 days from first symptoms, and most did so at ~14 days.
If you add 15 + 14 = 29.  Thus at about 29 days post-exposure most of the modern tests (even 1st generation) will have pretty high confidence.  If you factor in the person who had first symptoms at 28 days: 28 + 14 = 42 days (6 weeks).

The upshot is that 13 weeks is still the holy grail.  You never got fired for buying IBM (back in the day), likewise no one can dispute a 13 week window recommendation.  But there does seem to be strong evidence that 4-6 weeks is exceptionally encouraging with modern tests.