[Question #8710] Doctor says negative for all STIs but RPR shows positive. How can that be?

40 months ago

I have questions about the STI test results for one of my partners. She is a trans woman, and she and I are not exclusive (I know she has several other partners). For that reasons, we are very frank about our testing status and test results and always practice safe sex (as I understand it).

Today, I met with her and we engaged in mutual masterbation (no condoms) and took turns giving oral to each other (with condoms). That is the only activity we engaged in and we have never done anything else. We also discussed our testing status and she told me she just got tested and everything came back negative (she gets tested every 3 months for her PrEP). I feel like that is pretty safe.

After we finished fooling around, she told me she was willing to show me her test results on her phone (which I appreciated). But when I looked at them, they contained confusing information. Her doctor's comments on the top of the results said "All your STI tests are negative", but he went on to say, "It looks like your syphilis titer is permanently in the 4 to 8 range, FYI. If that ever increases significantly from 8 (by a factor of four... so, 32) we'd be worried about new infection." And the RPR results read like this:

RPR Screen ((A))

Positive

Reference Range: (Negative - )

03/28/2022 09:45

RPR Titer ((A))

1:4

Reference Range: (Negative - )

03/28/2022 09:45

Can you help me understand these results as they relate to what the doctor was saying? Should I be concerned about being exposed to Syphilis here or is this evidence of a previous infection, but nothing to worry about now?

I appreciate your guidance on this.

Edward W. Hook M.D.

40 months ago

Welcome to our foreign and thanks for your question. I agree with you that the activities you describe sound like safe, no risk events and would not be concerned.

I’ll be glad to help clarify things Guarding air partners syphilis tests.. Interpretation of syphilis blood tests can be confusing. The main stay of syphilis testing is called the RPR test. For diagnosis, This is one of two tests used to make a diagnosis of syphilis. Both tests must be positive to make a diagnosis. When only one test is positive they are referred to as being falsely positive.

Once a person has had syphilis, following treatment, the strength of RPR test positivity ( the titer) often but not always declines over time (months to years). Following successful treatment however, the RPR titer may not decline all the way to become negative/non-reactive and may remain positive at a relatively low titer. In such cases, if the person acquires syphilis again, the RPR titer may increase. Titers that increase four-fold indicate reinfection.

It sounds to me as though your Partner may have had Syphilis in the past and has stable, low Tigers. As her doctor indicated if the titers increase four fold, that would suggest reinfection and a need for reevaluation. And I hope this information is helpful to you. EWH

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40 months ago

Thank you for the clarification. I have just one follow-up question: even if my partner were currently positive for Syphilis (which it sounds like she is not), I would have to come into direct contact with a chancre to contract it, yes? Is there any way to transfer Syphilis without direct exposure to a chancre?

Edward W. Hook M.D.

40 months ago

Good question. syphilis is transmitted only through direct contact with a syphilitic lesion. further, syphilis is rarely acquired through oral sexual contact. Even less so when condoms are used as you did. EWH---

40 months ago

I understand that I should not worry about Syphils in my current situation, but for my education can you explain what reference range means in these results (the same ones I shared earlier but with clearer labeling)?

Is the reference range what indicates that this result should actually be read as negative despite the value saying positive? Also, what id the "Ind" column about?

Result Name: RPR Screen

Ind: ((A))

Value: Positive

Ref Range: (Negative - )

Result Name: RPR Titer

Ind: ((A))

Value: 1:4

Ref Range: (Negative - )

I promise this will be my last follow-up on this thread. I appreciate your answers to these questions.

Edward W. Hook M.D.

40 months ago

The term reference range refers to the expected result in a person who does not have syphilis. Thus the RPR expected range result is negative. Since a negative result does not have a strength (titer) to measure, the expected range for the RPR titer in a person who does not have Syphilis would be negative as well.

Admittedly, this is complex. Even experienced clinicians find challenges in interpreting syphilis test results. This is all the more so for results from persons who have had syphilis in the past.

Hopefully my responses have been helpful to you. Take care. EWH

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