What is difference between hiv 1 o 2 abs

Sounds like you are talking about an HIV antibody test. An “HIV 1/O/2″ antibody test is one designed to pick up antibodies to different strains of HIV, including HIV-1 Group M (the common one), HIV-1 Group O (a rarer variation) and HIV-2 (a different type of HIV which is uncommon outside of West Africa). Some older HIV antibody tests can miss some of the rarer HIV types – the newer HIV 1/O/2 types pick up pretty well all the types of HIV anyone is likely to have in a Western country.

When you run an HIV test like an ELISA (a common sceening test) you always get some reactivity – that’s the way the test is designed. If there’s only a little bit of reactivity the test is read as “non-reactive”. If there’s a lot then it’s read as “reactive”. The line between the two is the index value.

If your HIV antibody result (HIV 1/0/2 abs qual) is below the “index value” you can be confident it is negative. If it’s above, then you need to go on and do further tests to check whether you truly have HIV or whether the “reactive” test was a false positive. If the result is only about twice the “index value” it’s probably a false positive, but you can’t be sure without doing further testing.

Say the index value is 1.0. If you test at 0.4 or 0.8 then that’s a negative result, and you don’t need to do any further testing. If it’s 1.2 then the test is read as “reactive” and you need to do further tests to be sure whether you have HIV or not. Chances are, with a reading like that you don’t have HIV because it’s only a little above the “index value”. If it were 5.0 or 10.0 that would be more concerning.