index value for p24 Ag

[lisamarylee]

Hi does anybody know if the index value they give you for P24 Ag is important? I tested after a very low risk exposure on 77th day for both hiv1/2/o Ab(ELI) and p24 Ag ( ECL) and they both came back negative. I tested seperately for them and my p24 Ag came as

index = 0.5                                           reactive>1.0
                                                           0.9<borderline<1.0
                                                           non reactive<0.9

I've been really confused about this and I know that ECL is rather a sensitive test can someone tell me if th eindex is important?

[lisamarylee]

thanks a lot for the explanation..also do you know what the ECL test is? i searched online and apparently it is some type of western blot test but instead of giving me just an answer they gave me this index. ..what kind of western blot is this?..if its truly a western blot test and knowing that western blot tests are conclusive after 8 weeks I can just forget about the infection and move on with my life..!

[diver58]

As for your test results, a negative is a negative. The index values that you may obtain from your test results do not indicate the level of HIV antibodies/antigen in your blood (which is what the test is looking for). The index value, sometimes also called the "signal-to-cutoff ratio," is a technical term related to type of HIV-antibody test that is conducted. Most HIV test index values have a cut-off ratio of 1.0 and so values less than 0.90, like yours, are definitively negative. Values between 0.9 and 1.0 would be borderline reactive. And values above 1.0 would be preliminarily positive. These preliminarily positive (or provisionally reactive) tests require a confirmatory test before someone is told they are HIV positive. It does not matter how close the index reading was to 0.9 as that does not indicate that you are more or less likely to test positive at a later date. At the end of the day, a negative is a negative. The signal to cut-off ratio could be different for the instrument used for your test but it is normal for these values to fluctuate up and down from day to day and test to test. These values increasing or decreasing does not indicate anything and it is completely normal. If the test comes back non-reactive, that is the only part of the test result you need to focus on.

The above text I copied for you from a Canadian helpline

http://www.aidsvancouver.org/what-we-do/helpline/online/hiv-combi-pt-questionreally-worried

Hope this reply from
Stephanie
AIDS Vancouver Helpline Volunteer
should give you relief.

[lisamarylee]

thanks. I got freaked out cause i read a post where teak said the index value is blood contaminates including hiv and I searched google and found some research whatever papers with index values on them and hiv positive people also had the same index as i did for p24...do you know what affects that index.I remember being dehydrated when they drew my blood and my blood looked dark and thick..could that be it?

[diver58]

Cutoff point is 1.0 and anything less than 0.9 is Negative. These results never give "zero" results due to some interferrences. You should relax and believe your test, it clearly shows that you do not have HIV