Confused about HIV test Index Values

[murph125]

I never heard of index values for tests before.  I saw this on the Aids Vancouver online help section.  It seems like some test give a percentage ie .017 or something like that, and people seemed concerned about this even after a conclusive test.  I am just curious what this index measures and what does it mean.  It is possible that even if you test negative after a 3 month antibody test, that you can still have levels of the virus.  Are you telling me there are levels of positive and negative.  This question probably doesn't seem to make much sense but hopefully someone could explain.  I think everyone wants to know if they get a conclusive test it means they are truly HIV free, only to a certain level or percentage.  Thanks for any responses.  

[Teak]

No.

[murph125]

Thank you so much, this is one less thing to worry about.  Are these index number not typically give with rapid antibody tests?

[Teak]

Contaminants in the blood including HIV if present.

[nursegirl6572]

The index values are not important.  It has to do with how the test itself is processed.  All that is important is whether the index value falls BELOW the cut-off (negative), or above the cut-off (positive).  The index level will fluctuate every time you take a test, it is irrelevant.

[murph125]

Thanks, didn't make sense to me at all, espcially after 3 months.  What is the index actually measuring, the virus itself or some other type of antibody response etc?

[Teak]

No it doesn't make much sense and if one gets a conclusive negative test at three months post exposure then they are negative.