[Question #759] PCR/DUO at 28 days

53 months ago
Hi! 

On the 28th day after a low risk encounter, I took HIV duo Ab/Ag test, HBV Hbs-Ag test, HCV IgG antibody test and PCR qualitative tests for HIV, HBV and HCV. All tests came back negative. I just wanted to put the incident behind and move on, hence so many tests. Would the PCR tests take care of the smaller chance that the first three tests I list missed something at 28 days due to the window period?

Thanks!







Edward W. Hook M.D.
Edward W. Hook M.D.
53 months ago

Welcome to our Forum.  Congratulations for your commitment for testing to assure that you are maintaining your sexual health.  the answers to your questions vary a little by infection.  For ruling out HIV, a PCR would add nothing and might even be falsely positive at this junction.  A 28 day HIV Duo AG/AB test result at 28 days is definitive. 

For HBV and HCV, the need for testing at all is questionable.  Unless you have anticipated in receptive rectal intercourse there is virtually no risk for sexual acquisition of hepatitis C and therefore no need for testing.  If  you did receive rectal sex, then a PCR would likely become positive before the three month period at which HCV IgG tests results would be definitive.  As for hepatitis B, if you are vaccinated, you are not at risk and there was no need for testing to start with.  On the other hand, if you have not received the hepatitis B vaccine, then testing is reasonable.  Again, PCR might become positive before hepatitis B antigen is detectable but how much earlier has not been well studied. 

Personally and depending on the nature of your exposure, my advice at this time and assuming that your exposure was truly low risk would be to not test further, to accept the assurance that your tests so far provide and to move forward without concern.  All tests have occasional false positives which can cause their own harm and anxiety.

I hope this response is helpful.  EWH

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53 months ago
Dr. Hook, thank you for the response! The encounter was limited to me receiving strap-on sex from a female CSW and handjob. I started worrying after learning that HBV survives for some time outside the body, knowing that the strapon was used on other clients before me. It was already explained to me that this was only a theoretical risk exposure, but I decided to take the tests for peace of mind. I understand that this is more of an anxiety issue based on guilt at this time for me and am trying to address this separately with a specialist. 
I might have been vaccinated for HBV as a child, not sure though and even if yes, this would have been too long ago. In your opinion, what is the conclusive date to HBV test?
Thanks!

Edward W. Hook M.D.
Edward W. Hook M.D.
53 months ago
If you were born in the U.s. after 1992, and perhaps earlier you would have been vaccinated for hepatitis B

As far as testing is concerned, testing at three months will be conclusive and, I am convinced, will be negative.

Hope this helps.  EWH
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