Test Confusion

[ckorce27]

Hi Dr -

I keep reading all these things and let's say per chance you were still in the period where you only igM antibodies but not yet igG antibodies, a 2nd generation test would come back negative?  It wouldnt pick anything up at all?  I've read its like a 2 week window between the 2...

thank you

[H. Hunter Handsfield, M.D.]

Welcome to the forum.

You may be right that there is a period in which IgM but not IgG antibodies would be present.  To my knowledge, there are no data on whether early positive results with the antibody tests -- in the 10-30 day range -- result from detection of IgM, IgG, or both.  The important point is that nobody being tested for HIV should get hung up on such details.  The main difference between earlier ("2nd generation") and newer ("3rd generation") antibody tests is that 100% reliability is reached at ~8 weeks versus ~6 weeks.

Here is teh link to a recent thread that further discusses seroconversion time.  It should answer any further questions you may have about it.

http://www.medhelp.org/posts/HIV-Prevention/what-is-the-window-period-for-hiv/show/1704700

Regards--  HHH, MD

[ckorce27]

Hi Dr -

Thanks for the reply.  I have also heard that vaccinations can cause false positives. is there a window period where this wouldnt happen?  And if it does affect the ELISA test, would it also affect the western blot or IFA confirmatory tests?

Thanks again.

[H. Hunter Handsfield, M.D.]

Vaccinations have no known effect-- neither false negative nor false positive results.  Urban myth.

Don't overthink it.  There are no exceptions to HIV test reliability.  If you have been tested (within the timeframes discussed in that other thread), the result is reliable and there are no factor that will change it -- so that will end this thread.

[ckorce27]

Great, thank you!