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Differences/Accuracy of HIV testing

Mar 18, 2010

Dear Dr. Frascino,

Thanks for taking the time to answer questions. I have 2 different questions for you.

I had intercourse with a female 45 days ago (status unknown) where the condom broke. Within 24 hours I started combivir as a pep for 28 days. Normally I wouldn't worry about this but immediately after pep treatment concluded I developed swollen lymph nodes (neck and armpit), oral thrush, sore throat, slight fever, loss of appetite/stomach pains (and loss of 5% of body weight), tingling/numb hands and a slight rash. I took a antibody test at 30 days (result came back negative) and a p24 antigen test, proviral dna test and pcr viral load test at 39 days. The p24 antigen test and proviral dna test came back negative but the pcr viral load test could not be completed due to insufficient blood quantity provided.

First question, what is the difference between the proviral dna test and the pcr viral load test?

Second, how accurate are the test results that have come back (I know that the initial antibody test was within a potential window period but would pep affect the p24 antigen test or the proviral dna test/ how accurate are those tests)?

Thanks in advance for any insight you can provide.

-Going Crazy...

Response from Dr. Frascino

Hello Going Crazy,

Regarding question #1, see below.

As for question #2, a negative p24 antigen and qualitative PCR proviral DNA are extremely encouraging. However, I would still suggest you follow the recommended post-PEP testing guidelines (HIV-antibody test at six weeks, three months and six months from the date of exposure).

Good luck. Don't go crazy; you're nearly out of the proverbial woods.

Dr. Bob

please answer (RNA PCR versus DNA PCR 2009) Dec 14, 2009

dear doc bob

i had a risky hiv incounter from oral sex with a csw and drug abuser wich landed me with genital herpes 2 weeks later i started experincing a mono like illness so i went and had a 3 month antibody test wich came back negative symptoms still persisted for months later so i went back and had a complete std screen at 9 months wich also turned out negative except for the herpes so my doc refferd me to a i.d specalist who did a hiv rna quanative with a hiv 1/2 ab test he also did a cbc with differintal and a hep panel and ebv panel.the hiv rna was undetectable down to 48 copies and everything else was negative except for the ebv wich reads (ebv)vca ab (igg)3.77 ebv (ebna)ab,igg 5.00 and ebv ab,vca (igm)0.90 in range.interpatation says suggestive of a past infection but doc says that it looks like i'm just getting over i asked him to do a hiv dna pcr and he stated that a dna would never show posotive over a rna and that the rna was the gold standard to pcr testing.but i know that the viral load test is not a diagnostic test and the only pcr test for diagnostic purpose is the hiv rna qualative test by abott.can you please shed some light on my situation from your expertise on my assesment.will donate

Response from Dr. Frascino


Oral sex is considered to carry only a very minimal risk for HIV transmission/acquisition. Genital herpes is much more easily contracted via oral sex than HIV.

The sensitivity and specificity of HIV PCR DNA (qualitative) and HIV RNA PCR (quantitative) test are similar, although studies indicate that the HIV DNA PCR might have the slightest edge in sensitivity. (DNA PCR sensitivity is greater than 99% while RNA PCR sensitivity can range from 95% to 98%). I tend to use these two tests for different purposes. The HIV PCR RNA is used primarily to quantify HIV replication while the HIV PCR DNA is used to help sort out unclear or indeterminate HIV-antibody test results. Neither HIV DNA PCR nor HIV PCR RNA is recommended for routine HIV diagnostic screening. The best test for HIV diagnostic screening remains the HIV-antibody test taken outside the window period.

Thanks for your desire to make a tax-deductible donation to The Robert James Frascino AIDS Foundation ( It's warmly appreciated. In return, I'm sending you my good-luck karma that your definitive and conclusive HIV tests remain negative.

Happy Holidays.

Dr. Bob

Question on blood test..
Re: HIV transmission Risk, WILL DONATE (CASUAL CONTACT, 2010)

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