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How reliable is the HIV DNA RT PCR test? Negative SRD check

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General & Family Physician
Practicing since : 1978
Answered : 6592 Questions
Hi I've been reading contradicting information about the HIV PCR test. I have read that it can detect the virus within 72 hours and is most accurate at 28 days. I had a HIV DNA RT PCR test done 4.5 days after possible exposure because I suffer from anxiety and couldn't wait. My results were HIV 1/0/2 ABS-Index Value <1.00 and HIV 1/0/2 ABS, QUAL Non-Reactive. How reliable is this test within the time I took it? I know I need to follow-up with an antibody test in 4 weeks but can I relax unitl then? I still have 2 weeks left to wait. And I also took a full panel SRD check and everything came back negative. Is there any STD tests that I need to redo because I know all tests have a window period?
Posted Sun, 23 Sep 2012 in HIV and AIDS
Answered by Dr. Pavan Kumar Gupta 1 hour later
Thanks for the query.
In fact p24 antigen test and PCR or HIV NAAT are two tests which detect HIV at the earliest.You can even go for these test at around 10 to 14 days.

The HIV p24 antigen test, the most widely available of the two, is designed to detect a protein (the p24 protein) associated with HIV. The p24 antigen test can detect the p24 protein on average 10 to 14 days after infection with HIV.

A PCR test (Polymerase Chain Reaction test) can detect the genetic material of HIV rather than the antibodies to the virus, and so can identify HIV in the blood within 7 to 14 days of infection. The test is also known as a viral load test and HIV NAAT (nucleic acid amplification testing).

You are very right that you have got the test done in window period.
Ultimately go for HIV DUO test after 28 days which has a very superb rate of accuracy.

You are most welcome to ask any follow up query.
Best of luck

Above answer was peer-reviewed by
Follow-up: How reliable is the HIV DNA RT PCR test? Negative SRD check 28 minutes later
So the HIV test that I had taken isn't considered to be accurate? With a negative test at 4.5 days after possible exposure isn't a good indicator for me? What about the STD tests that I had taken, are there any tests that I need to retake? I was tested for HPV, Gonorehhea, Claymidia, Syphillis, Trich and all Hepatitis and they were all negative.
Answered by Dr. Pavan Kumar Gupta 3 hours later
Yes,the test you undertook for HIV has no relevance and you have to get proper test at proper time.
Unfortunately the question of when to get an STD test is not easy to answer. To start with, STD testing isn't perfect - even if you have theoretically waited long enough for a test to work you could still end up with a false positive or a false negative. Then you need to account for the fact that not all STD tests work in the same way. Some tests look directly for the presence of a pathogen, while others look for your body's immune response to the infection( look for the antibodies ) .
Being able to answer how long it would take for someone to definitively test positive or negative on an STD test after a risky sexual encounter would require knowing a number of things which is beyond the scope of our discussion on this forum.

Common practice suggests that people could go in for basic testing for bacterial STDs as soon as 2 to 3 weeks after an exposure - sooner if they have symptoms - but that they would need to be retested again at least three to six months out in order to feel relatively certain of their results. At a month out, some tests for chlamydia and gonorrhea would be reasonably accurate, but tests for other diseases such as herpes and HIV take longer to become conclusive.

I would advise you to consult a doctor and discuss this issue with him and plan your investigations accordingly.
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