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HIV test. Can it be trusted? Can the potent antiviral impact extend the window period?

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Practicing since : 2003
Answered : 301 Questions
hello doctor!
im confused and scare about hiv testing in general.
Q1 : what is the guideline to be 100% sure abut results? is it 3 month (90 days) or 12 weeks (84 days) or is it 6 month (180 days) or 24 weeks (168 days)
Q2 : Can i rule out this as the sum of all my fears? I have tested 3 times. First test 7 days after exposure. Method was Rapid Test with a full blood extraction. Result was very weakly reactive and lab said not conclusive.
I tested same day negative with a Lab Base EIA test, 3rd Generation.
I tested negative 88 days after, same Lab EIA test.
Q3. Can this event/medication extend my window for testing? In between tests and 63 days after potential exposure, i had a rash that dermatologist said chicken pox. I wanted to die as i have previously read that rashes are part of HIV seroconversion symptoms. Bumps crusted over however at day ten, and fever only lasted a day. Eventually dermatologist said chickenpox, which is still an awkward and very disconforting coincidence. Anyway, i took a medicine called brivudine, which is similar to acyclovir for 7 days and im afraid that this potent antiviral impact window for testing.. Is it possible?
thanks for your time and sorry if i was too lengthy with questions

just one extra question.
can a analyst see antibodies with 'manual rapid test' that are undetected with lab based EIA test? i hear there are cut offs and so on...
sorry if it sounds stupid, but im very anxious!
Posted Tue, 22 May 2012 in HIV and AIDS
Answered by Dr. Rohit Batra 13 hours later

Thanks for writing in.
I understand your concern.
HIV tests are usually carried out after 12 weeks after exposure.
At times, tests can be non-conclusive and at such times, they should be repeated as was done in your case.
Now since the result was negative, there are remote chances that it too was false negative. In some people, antibodies take about 6 months to form ( although this happens very rarely) and I would suggest that you get yourself re-tested to allay your fears and put aside all doubts.
Chicken pox usually occurs in periods of stress, when the immunity is low (normally). It occurs in children in exam days when they are worried. So it is possible that stress could be a precipitating factor in your case.
The drugs that you have taken have no effect on the production of antibodies against HIV (which are detected in usual laboratory tests). Thus, they will have no effect on your window period.
The sensitivity and specificity of the manual rapid test is similar to the EIA. However, we cannot conclusively tell anybody with a positive test that he/she is infected particularly if he/she belongs to a population where not many people are HIV positive.
I would suggest that you don’t worry about this weakly positive test. It can be a false positive as well.
Hope I have answered all your queries.
Above answer was peer-reviewed by
Follow-up: HIV test. Can it be trusted? Can the potent antiviral impact extend the window period? 2 hours later
hello doctor, thanks for your answer. i have two more questions, please advice if i need to open another query.
i thought i had this behind as my 88 days test came out negative. the problem is the initial false positive. i can't believe im even thinking that lab people messed up my test twice and that is why is negative.
please doctor, two more questions. could you advice what exactly is 6 month? are we talking about 24 weeks? the effect of extra days is 2 weeks in 6 months vs 3...
Also, if my risk event was 24 weeks ago, and test happened at 90 days (first 2 : weakly rapid and confirmatory EIA negative) and 168 days (EIA negative), would i've be 100% of the hook?
Answered by Dr. Rohit Batra 2 hours later
Thanks for writing back.

The days in weeks are the minimum cut off XXXXXXX for a test to show results.
When we talk to patients, the weeks change into months and hence 12 weeks become 3 months. Now if a test can show a positive result at 12 weeks, it will also show a positive result at 3 months.
If all your tests have been negative till date except the one which was non equivocal, you need not worry and take yourself as non reactive.
I hope I have addressed your concerns.


Dr.Rohit Batra
Above answer was peer-reviewed by
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