hiv dna pcr and antibody testing after sexual assault

My daughter was sexually assaulted and took an hiv dna pcr test and an antibody test 32 days after possible exposure. I know the hiv dna pcr test is not a diagnostic test but since she took both tests shouldn't that help to alleviate some of her anxiety? I was told the dna pcr test is pretty conclusive after 28 days. If the dna pcr test is so unreliable, why is it used for testing for blood donors in my area to help shorten the window period? Thanks for any responses.

[boomie24]

I'm really, really, sorry to hear about your daughter. I hope she's doing alrite.
I wouldnt know how much that test would be reliable less than a month after the exposure, really. Sorry. But I guess the safe way to go would be to redo the test 3 months after exposure.

[tomMulligan]

Your blood will normally have been tested first using the ELISA test. It’s quite cheap, and also has the advantage of being very sensitive. Provided your test is performed long enough after your exposure to HIV for antibodies to appear in 3 months, the ELISA test will almost certainly detect them. Two terms are used to describe the accuracy of tests: ‘sensitivity’ and ‘specificity’. The ELISA test is very sensitive (99.5 per cent) meaning it will detect even very small quantities of HIV antibodies. But, because the ELISA test is so sensitive, it has less specificity which means there’s a chance that it could produce a small number of false-positive results. Because of this a second type of HIV test, the Western Blot, is performed on all samples that test positive for HIV antibodies using the ELISA test. The Western Blot test confirms if a sample is positive or negative. Very rarely, a result comes back ‘indeterminate’, meaning a person has just started to develop antibodies to HIV because it is so close to the time when they were infected. If this happens, the person will need to be re-tested outside the three-month window period it can take for HIV antibodies to develop. False-positive tests are exceedingly rare after a Western Blot test.

Please take note that Qualitative HIV PCR DNA is not FDA approved for HIV-diagnostic testing; however, it can be very helpful in sorting out unclear or indeterminate HIV-antibody test results.

[tomMulligan]

When used together in the right time, the results from this two-part testing are greater than 100% accurate. The HIV antibody EIA is a screening test and the HIV antibody Western blot is a confirmatory test. Results from an HIV antibody EIA test should never be used alone to report a positive final result.