Testing reports conclusive?

[dolitaire]

Hello Doctor,

I got an injection in a local clinic in India, but I failed completely to see whether the nurse had used a new syringe or not. She asked me to sleep on the bed in the clinic and I was facing the other side when she gave me the injection on my buttocks.

Terrified, I got myself tested using HIV ELISA antibody test after 60 days of exposure, which turned out to be negative. On the 83rd day post exposure, I got another HIV ELISA antibody test done ( test report said that the test detects both HIV I and HIV II antibodies), which turned out be negative as well. I called up the lab (which did my  HIV ELISA antibody test on the 83rd day post exposure) yesterday and they told me that the kit they were using was of a make of an Indian company called Span Diagnostics.

I called up the same company's helpline today and they told me that the company makes only 2nd generation HIV ELISA testing kits. My questions are:
1) Do I need further testing or can I consider my report as final and conclusive?
2) What is the window period for a second generation HIV ELISA antibody test?
3) Is 83 days as good as 90 days for a conclusive test report using a a second generation HIV ELISA antibody test?
4) What are the differences in terms of window period for second generation, third generation and forth generation HIV tests?

Thank you very much!

[H. Hunter Handsfield, M.D.]

You understood exactly right.

Thanks for the thanks.  Take care.

[dolitaire]

Thank you doctor. It feels awesome to hear this information from a professional and an expert like you in the field.
Just a question: So what I understand from what you have said above is irrespective of whether the test is a  2nd generation HIV antibody test or a 3rd generation HIV antibody test, it is 100% accurate post 8 weeks after exposure right?

[H. Hunter Handsfield, M.D.]

Welcome to the forum.

India is a medically sophisticated country and injection equipment re-use is rare.  There was an instance reported in which a number of persons acquired hepatitis B due to used equipment supplied by an unscrupulous company, but to my knowledge that is the only instance.  And it is unlikely any doctor's office or clinic routinely re-uses equipment.  Even in India or other developing countries, there is little economic incentive for such cheating; injection equipment costs pennies.  So I believe you overreacted; there was no need for HIV testing.  (And anyway, if this concerns you, HIV is a much lower risk than hepatitis B or C.)

That said, your negative test result at 83 days is 100% reliable.  My guess is you actually had a 3rd generation antibody test; I'm not aware of any 2nd gen tests that include HIV-2 (although I suppose such tests may exist in India).  But even this doesn't matter.  The difference in 2nd and 3rd gen antibody tests is in shortening the front end of the seroconvesion window -- i.e. the reliability of results before 4-6 weeks.  All antibody test types are equally accurate after 6-8 weeks, with virtually 100% reliability (even though official advice usually is for definitive results at 3 months).  Below I have provided the link to a thread that discusses this in detail.

Those comments answer all your questions, but so there is no misunderstanding:  1) Your negative result is conclusive; no further testing is needed. 2,3) See above and the link below. 4) See above.

Here is the link about window periods:  http://www.medhelp.org/posts/show/1704700

I hope this has helped.  Best wishes--  HHH, MD