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3 week Hiv Ag/Ab combo
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3 week Hiv Ag/Ab combo

Hello all,

I recently posted a question to doc HHH on the monitored forum:
http://www.medhelp.org/forums/HIV/messages/776.html

Today (three weeks post exposure) I had a HIV Ag/Ab Combo test: Negative (0.29). They told me at the lab that anything below 1.0 is negative

I've heard that these combo tests can pick up an infection very early by detecting antigens. I read an article online which said that these tests can pick up an infection in as little as a week!

How confident can I be in this three week result?
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Avatar_n_tn
The theory behind these 4th generation dual Ab/Ag tests is that the Ag picks up a large chunk of the HIV+ people that aren't picked up by the Ab test. I'm not familiar with the data at 3 weeks, but at 4 weeks, the Ab tests would pick up 80% of HIV+ves, while the Ag tests pick up 75%, so combined they pick up 95% of HIV+ people.

At 3 weeks, the ratios would be different - the Ab test would pick up less, probably in the region of 50%, but the Ag test may pick up more. Maybe other posters will have greater knowledge on this.

I can't put a number on it, but I would say that the negative is very encouraging, but not conclusive.
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Avatar_n_tn
Yes. This test is based on the theory that antigen and antibody have reverse correlation, i.e. when antigen is high antibody is low, vise versa.

So antigen show poz when antibody is below detectable level, and antibody show poz when antigen is suppressed. So theoretically it will shorten the window period to the first minute antigen increased to detectable level after exposure, which is a few days to 2 weeks after exposure.  But there is also risk that antigen decreases to below detectable level before antibody increases to detectable level, i.e. the second gray/indeterminate period after the initial window period, which may occur between 2-4 weeks, though not very probable.

It is said that this test should be accurate after 4 weeks (I believe it is the test used in NY) for most people. And three week is very encouraging.

Just FYI.
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Avatar_n_tn
Thanks guys,

My exposure was low risk anyway, vagina to anal contact via fingering,.. doc HHH said:

'You do not need testing, except for peace of mind-that is if you would sleep better knowing the result of a lab test, go ahead and have it done, you can count on a negative result'

I also see on wikepedia (dont know how reliable the info is) that the window period for Ab test is stated as ave 22 days, and for Ab/Ag it says 16days
I know these are averages but it is encouraging that I have a neg Ab/Ag at 22 days.

Considering the low risk maybe I should put this behind me now rather than going through the ordeal of testing again in a week or two?

The doc also said it was safe to have unprotected sex with my wife now!
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Avatar_n_tn
If you can do that (just let it go), I would. There are no documented cases of HIV transmission through hand-genital contact.

Take care.
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