Sign-in to Ask A Doctor - 24x7
OR
Sign in with Google
What Causes False Positive Test Result For TPHA?
Question: Dear Doctor,
I'm 47 years old, male and I received the result of a blood test done on 15/07/2015 with the TPHA Positive. I don't have any sexual risky behavior and I never had any symptom of syphilis as ulcers (chancre) in the genital area or in any other part of my body (never).
I'm working in XXXXXXX and more or less 2,5 weeks before the blood test, I developed an intestinal infection characterized by a strong diarrhea and cramping during about two weeks. I had a medical appointment and doctor prescribed me an antibiotic (Ciprofloxacina Ciclum 500 mg). I finished the treatment one day before the blood collection.
I'm again in XXXXXXX and on 10/08/2015 I repeated the blood analysis. As there is no possibility, for technical reasons to confirm here the TPHA, I made the VDRL with a negative result.
Is it possible to have your advise please ? Should I be worried with a TPHA (+) and a VDRL (-) after 25 days ?
Many Thanks in advance.
Kind regards,
XXXX
I'm 47 years old, male and I received the result of a blood test done on 15/07/2015 with the TPHA Positive. I don't have any sexual risky behavior and I never had any symptom of syphilis as ulcers (chancre) in the genital area or in any other part of my body (never).
I'm working in XXXXXXX and more or less 2,5 weeks before the blood test, I developed an intestinal infection characterized by a strong diarrhea and cramping during about two weeks. I had a medical appointment and doctor prescribed me an antibiotic (Ciprofloxacina Ciclum 500 mg). I finished the treatment one day before the blood collection.
I'm again in XXXXXXX and on 10/08/2015 I repeated the blood analysis. As there is no possibility, for technical reasons to confirm here the TPHA, I made the VDRL with a negative result.
Is it possible to have your advise please ? Should I be worried with a TPHA (+) and a VDRL (-) after 25 days ?
Many Thanks in advance.
Kind regards,
XXXX
Brief Answer:
Most likely yours is a false positive TPHA
Detailed Answer:
Hello. Welcome back.
I have taken note of your query and I have understood it.
I have answered your previous related query too wherein I suggested you to undertake RPR/ VDRL (Non-Treponemal test) and FTA-ABS test (Treponemal test).
Though TPHA is a syphilis specific test however there can be cases with false positive and false negative results.
A positive TPHA in the absence of a history of chancre Or a risky sexual behavior should be followed by RPR/ VDRL test and another of a Treponemal test i.e syphilis specific test like FTA-ABS test.
If these follow up tests are negative then 3 scenarios arise i.e...
1. False positive TPHA
2. A very early primary syphilis
3. Distant past syphilis
Since you don't have any history of a risky sexual behavior therefore scenario no. 2 and scenario no. 3 are ruled out.
Most likely yours is scenario no. 1 i.e false positive TPHA.
Regards
Most likely yours is a false positive TPHA
Detailed Answer:
Hello. Welcome back.
I have taken note of your query and I have understood it.
I have answered your previous related query too wherein I suggested you to undertake RPR/ VDRL (Non-Treponemal test) and FTA-ABS test (Treponemal test).
Though TPHA is a syphilis specific test however there can be cases with false positive and false negative results.
A positive TPHA in the absence of a history of chancre Or a risky sexual behavior should be followed by RPR/ VDRL test and another of a Treponemal test i.e syphilis specific test like FTA-ABS test.
If these follow up tests are negative then 3 scenarios arise i.e...
1. False positive TPHA
2. A very early primary syphilis
3. Distant past syphilis
Since you don't have any history of a risky sexual behavior therefore scenario no. 2 and scenario no. 3 are ruled out.
Most likely yours is scenario no. 1 i.e false positive TPHA.
Regards
Above answer was peer-reviewed by :
Dr. Vinay Bhardwaj
Dear Doctor,
Thank you very much again for your support.
The problem is that it is impossible to undartake a FTA-ABS test (Treponemal test) here in Angola, just the VDRL is possible...
Do you suggest to repeat the VDRL in a few weeks ?
Kind regards,
XXXX
Thank you very much again for your support.
The problem is that it is impossible to undartake a FTA-ABS test (Treponemal test) here in Angola, just the VDRL is possible...
Do you suggest to repeat the VDRL in a few weeks ?
Kind regards,
XXXX
Brief Answer:
Do not repeat VDRL; most likely a false positive TPHA
Detailed Answer:
Hi.
As a rule...A positive TPHA in the absence of a reactive VDRL is most likely a false positive, in absence of previous syphilis infection.
Apart from false positive TPHA, a positve TPHA and negative VDRL test result would be possible in 2 scenario i.e
-Very early primary syphilis and
-Very Old infection.
In very early primary syphilis VDRL/ RPR would be falsely negative if it is done too soon after infection i.e before antibodies have appeared. It will subsequently turn positive and therefore a repeat VDRL would reveal a positive result later on. However, since there is no history of a recent risky sexual encounter in your case, hence no chances of a new syphilis infection in you and therefore I won't suggest you to repeat VDRL as it will be negative again.
In your previous query to me you mentioned about a risky sexual contact 6 years ago. Assuming that as a possible old syphilis infection (just in case), this type of scenario i.e TPHA is +ve, VDRL is non-reactive, can also arise in case of a very distant/ old infection!! Therefore, ideally you should also undergo a different syphilis specific test from TPHA i.e FTA ABS. If FTA ABS is negative that would stamp you as not infected! Unfortunately FTA ABS is not available with you.
Having said that it is highly unlikely that a chancre on external genitalia of a heterosexual male would go unnoticed, therefore, your sexual contact 6 years ago can be assumed to be clean and since it was your only risky sexual contact hence your recent TPHA test is most likely a false positive.
I would suggest your wife to test for VDRL and TPHA and a negative report for these would further substantiate the fact that your test was false positive.
Regards
Do not repeat VDRL; most likely a false positive TPHA
Detailed Answer:
Hi.
As a rule...A positive TPHA in the absence of a reactive VDRL is most likely a false positive, in absence of previous syphilis infection.
Apart from false positive TPHA, a positve TPHA and negative VDRL test result would be possible in 2 scenario i.e
-Very early primary syphilis and
-Very Old infection.
In very early primary syphilis VDRL/ RPR would be falsely negative if it is done too soon after infection i.e before antibodies have appeared. It will subsequently turn positive and therefore a repeat VDRL would reveal a positive result later on. However, since there is no history of a recent risky sexual encounter in your case, hence no chances of a new syphilis infection in you and therefore I won't suggest you to repeat VDRL as it will be negative again.
In your previous query to me you mentioned about a risky sexual contact 6 years ago. Assuming that as a possible old syphilis infection (just in case), this type of scenario i.e TPHA is +ve, VDRL is non-reactive, can also arise in case of a very distant/ old infection!! Therefore, ideally you should also undergo a different syphilis specific test from TPHA i.e FTA ABS. If FTA ABS is negative that would stamp you as not infected! Unfortunately FTA ABS is not available with you.
Having said that it is highly unlikely that a chancre on external genitalia of a heterosexual male would go unnoticed, therefore, your sexual contact 6 years ago can be assumed to be clean and since it was your only risky sexual contact hence your recent TPHA test is most likely a false positive.
I would suggest your wife to test for VDRL and TPHA and a negative report for these would further substantiate the fact that your test was false positive.
Regards
Above answer was peer-reviewed by :
Dr. Vinay Bhardwaj
Dear Doctor,
It's clear. Thank you very much for your important support.
Kind regards,
XXXX
It's clear. Thank you very much for your important support.
Kind regards,
XXXX
Brief Answer:
You are welcome
Detailed Answer:
Thank you for writing to us.
Regards
You are welcome
Detailed Answer:
Thank you for writing to us.
Regards
Note: Consult a Sexual Diseases Specialist online for further follow up- Click here.
Above answer was peer-reviewed by :
Dr. Vinay Bhardwaj
Answered by
Get personalised answers from verified doctor in minutes across 80+ specialties
