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Blood test showed syphilis positive. Not had sex. Chance of false positive?

Jul 2012
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Practicing since : 1993
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I had a blood test two days ago and qualitative result show positive for Syphilis. I am now undergoing the quantitative test. I have not had sex for the last 3 weeks. I have no symptons. What is the chance that the initital result is a false positive ? If the further test is positive, what does it mean ? Do I then need treatment ?
Posted Tue, 2 Oct 2012 in Sexually Transmitted Diseases
Answered by Dr. Praveen Rodrigues 53 minutes later
Hi there.
By qualitative test, i presume you ae referring to STS (RPR/VDRL) tests? If positive, then the titre needs to be noted. The test is redundant without the titre levels eg 1:8, 1:16, 1:32 etc & the titre level is also important should you require treatment to evaluate progress subsequently using falling titres.
Again, the next test you are attempting is possibly TPHA or TPI tests that you consider 'quantitative'. Your medical & Sexual Exposure history & Clinical features have all to be taken into account along with the tests to decide if at tall you suffer from Syphilis, what stage is it at & then accordingly, the treatment will have to be instituted.
The incubation period is anywhere upto 90 days or afraid it is a bit not having had sex in the last 3 weeks does not hold any significance. However, if positive, one has to trace your history & evaluate & treat any partners' therof.
Yes you need treatment if both sets of test are positive but as i said in keeping with the clinical history & assessment. It is very feasible that false positive results arise in these tests but so are false negatives. An overall picture wil emerge with titres & Past History & my answer is if it is positive by two tests & in titres that are of significance, then Yes it is better to be treated. Do hope this answers your queries. Godspeed & do remember to use protection & practice safe sex in the future in your interests. Cheers!
Dr Praveen Rodrigues MD
Dermatologist & Venereologist,
Bangalore, India
Above answer was peer-reviewed by
Follow-up: Blood test showed syphilis positive. Not had sex. Chance of false positive? 1 hour later
My next test is FTA-Abs
Answered by Dr. Praveen Rodrigues 3 minutes later
Hi there. Fine..let me know the result. Also, what was the titre in your first test? I presume you are seeing a dermatologist/venreologist on the ground. You will have to provide a detailed sexual history prior to all this testing as it is unclear why all this was done..was it on suspicion of any STD or routine? If the former, then Yes, it is best you get treated ir-respective. Cheers & hope this answers your queries. Good Day!
Dr Praveen Rodrigues MD
Above answer was peer-reviewed by
Follow-up: Blood test showed syphilis positive. Not had sex. Chance of false positive? 23 minutes later
It was discovered during a regular blood test for employment visa application. I do not thave the titre date that you refer to.
and it sounds like from what you said, even if the FTA-Abs test is negative, there is still some potential infection ? So if the FTA-Abs is negative, should I still go for other tests ?
Answered by Dr. Praveen Rodrigues 1 hour later
If you do not have the titre, please repeat the initial test & get it done WIT a titre. Then, do a TPHA. Once you have both tests, it will be clear whether to treat or not to treat.
If on the other hand, it is for employment purposes, you have no other option but to treat & show that you have falling titres & hence more than one reason to repeat the first type of test & with a titre (date of titre not important) to help in both diagnosis & follow-up.
Hope this is clear. No need to speculate whether to treat or not if for employment purposes ( & am guessn here the gulf...have been to that part of the world)...cheers & GOOD lUCK!
Above answer was peer-reviewed by
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