[Question #5401] RPR False Negative test fear

75 months ago

I have a severe anxiety disorder about STDs - I want to personally thank both Dr. Hook & Dr. Handsfield for answering questions over the years on forums. My anxiety stems from the guilt of frequenting female prostitutes from around 2002 - 2009 before I met my wife. I always used a condom for intercourse - I was tested many times during that period and am certain I am HIV, etc, negative. That leads me to Syphilis - I had two RPR tests one in 2013 and another in 2014, both were negative. Then I read an article that talked about the reverse algorithm and how labs screen with the TPPA first confirm with the RPR (I didn’t have a test this way) – I then saw tables that showed the sensitivity of the RPR test 72% for very late stage syphilis. Since my tests were all taken anywhere from 6-12 years after the exposures (which really probably weren't since I used a condom) - I got scared that 72% sensitivity and what I read that my RPR tests could be a false negative. Then I saw this post from H. Hunter Handsfield, M.D. Aug 31, 2005 “RPR turns positive early in syphilis, then gradually becomes weaker over the years. Sometimes it becomes entirely negative, even without treatment. However, if the disease reactivates as tertiary syphilis, the RPR almost always becomes positive again. A negative RPR is strong evidence against active syphilis; the exceptions are rare." What scares me is if I was one of those people who turned negative without treatment and my RPR was a false negative because of this – what is the likelihood the disease could re-activate? I know it would be easy to just get the TPPA – but my anxiety over testing is tremendous and I don’t want to open all these wounds again if not necessary – I have never had symptoms – no chancre ever - is my two negative RPR's (6-12 years from supposed exposures) valid - am I okay?

H. Hunter Handsfield, MD

75 months ago

Welcome to the forum. Thanks for your confidence in our services.

As you obviously understand, tyhis is your OCD/anxiety speaking. You describe sexual practices and lifestyle that make syphilis exceedingly unlikely. Not only were the specific practices (fingering, condom protected sex) safe, but syphilis is rare in heterosexual women and female sex workers, and was even more so in the years you are concerned about, when most syphils in the US was occurring in men having sex with men. And while you correctly quote me about the natural course of RPR positivity in infected people, that course takes decades, not just a few years. Having been "exposed" only 6-12 years ago, there has not been enough time for the RPR to show infection and then regress to a point it cannot be detected. There is no chance you have syphilis or that it will reactivate in teh future. So no worries: you're OK!

I hope this information is helpful. Let me know if anything isn't clear.

HHH, MD

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75 months ago

Dr. Thank you so much for everything you have done over the years, I have had terrible anxiety fear for twenty years because of guilt in sleeping with prostitutes and I have read your posts for years - some of them are hilarious in how you answer the same questions people with OCD have over and over with great patience - you are a wonderful doctor. I just had two other questions - (1) since I had two negative tests that eliminates any chance of Prozone correct (you answered this once before to someone else - but people with OCD sometimes need re-assurance (2) I also have had unexplained rashes from 2010 to 2017. I had what doctors told me where athlete’s foot on soles of feet and then strange rashes on my legs and buttocks were never truly identified but were thought be atopic dermatitis. The dermatologists never mentioned syphilis, or suggested I get a test so I didn't for awhile, then finally did in 2013. The rashes were never ones that looked like syphilis – red patches but never copper penny shaped or brown in any color, just red scaling rash that was sometimes itched when I scratched - i would take steroids and in 2-3 days they always disappear, and always in winter and never on the palms of the hands or any upper extremities. The rashes were also years after the exposures - So this rash cannot be from syphilis correct? And from the previous answer there is no reason for me to get a TPPA test because the time period involved to get to where the test could be a false negative is much further beyond when I took the test and thus when I tested the sensitivity of the RPR was almost 100% correct? Thus no reason to get a reverse algorithum test correct?.

H. Hunter Handsfield, MD

75 months ago

Syphilis would never explain a rash that might mimic athlete's foot or other things like you describe. Second, the RPR is NEVER falsely negative in people with active syphilis causing rash or other symptoms. Your negative RPR proves your rashes are due to something else. There is no need for TPPA or any other confirmatory blood test -- it would be a waste of money. Having said that, if a negative result will further reassure you, of course you are free to do it. Do not tell me (again) that you're hesitating because of fear of being tested. I have no patience with such cockamamie irrational reasoning about tests for feared medical outcomes (whether it be syphills, HIV, mammography in women with breast lumps, or anything else). If you fee you need to do it, just do it and don't ruminate with me about your fears over it.

Finally, please do your best to stop asking "what if", "yes but", or "could I be the exception" sorts of questions. Your mental status is going to create such scenarios -- its in the nature of OCD and anxiety that repeating the facts of the case don't help, but just create more opportunities to think of exceptions. No matter what you think up, the answer always will be that you don't have syphilis. There are no possibilities that woudl change this -- so time to stop asking! OK?

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75 months ago

last question two negative RPRs would eliminate any chance of the rare prozone effect correct? - and thank you so much for your patience - you are correct about testing - its stupid for me to feel that way - thank you so much for all you have done for me and people like me over the years..........and sorry if I tried your patience - again you are wonderfully patient and I appreciate it very much.

75 months ago

thanks again for your patience with me, I feel so much better now

75 months ago

You can close this out now - I know Prozone is irrelevant not sure why I even asked............thank you so much for all you have done for so many people over the years - I appreciate it very much. Thanks again Dr. Handsfield, it was an honor to have you answer my question. take Care.

H. Hunter Handsfield, MD

75 months ago

Prozone is not a problem. You have over-interpreted something you found online. It hasn't been a problem for at least 2-3 decades. First, RPR is almost always accompanied by Igg/IgM (ELISA) testing, even if such results are not reported, and these tests are not subject to prozone. Second, virtually all labs routinely take the required steps to prevent prozone when performing RPR or VDRL. This is never something to be concerned about.

That concludes this thread. It will have to be your last about your past exposure and concerns about syphllis and testing for it. Thanks.

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