-7/10 negative Labcorp venereal screening (includes HIV and RPR)

-7/10 equivocal Lyme result for IgG.  10 days doxycycline given on 7/13

-8/8 Lyme blot abnormal for IgG p41 ab

Questions:

1. How reliable is Labcorp RPR?

2. Any concern that IgG p41 Ab from Lyme blot is something else (unknown old syphilis or new from 6/22)?

3. If my perceived ARS “symptoms” were actual ARS then my tests would have been positive correct?  Meaning negative test shows symptoms are actually not ARS?

The bottom lines:  Almost certainly you have neither HIV nor syphilis, although both tests were done a bit early. The HIV test should be repeated 6+ weeks after exposure, i.e. any time now. (Current results are 98-99% reliable, but 6 weeks is required for conclusive proof.) Since doxycycline is 100% effective in treating or preventing syphilis, there is no point in repeat RPR or other test for syphilis. In any case, with condom protected oral sex, there was no risk at all for any STI; had you asked ahead of time, I would have advised there was no chance you were infected and no testing was necessary for either HIV or syphilis. But assuming you still want conclusive test results, 6+ weeks is needed for a conclusive HIV test result.

I have no comment about Lyme disease:  we're STD experts and I'm not completely confident about Lyme antibody testing. Is that why the doxycycline? Were you under the care of an infectious diseases specialist or someone else who understands the complexities of Lyme diagnosis and treatment? If so, follow that doctor's advice.

Your questions make me wonder if you misunderstand antibody testing. IgG antibody (i.e. immunoglobulin G) is the basis for most antibody tests for a hundred or more different infections. Just because the terminology is similar doesn't mean your positive IgG for Lyme p41 has anything to do with HIV or syphilis diagnosis. It does not.

1) Just about every lab worldwide uses exactly the same RPR tests. Labcorp is neither more nor less reliable than any other facility. The test is highly reliable -- but it does take up to 6 weeks for RPR to become positive in newly infected persons.

2) See above. Your Lyme test result has nothing to do with syphilis. Check with your doctor.

3) Correct:  ARS symptoms are not caused by the virus, but by the immune response. And the immune response is measured by antibody. It is not possible to have ARS with negative antibody testing. In other words, your negative HIV tests prove that whatever symptoms you have had or might develop in the future are not caused by HV/ARS.

I hope these comments are helpful. Let me know if anything isn't clear.

HHH, MD

Sincerely thank you for your prompt reply. There is so much (Mis)information available it’s hard to know what to believe.  My preoccupation with p41 came from the various info available: depending on what you read- you can be perfectly healthy and test only for p41, or you can have hiv/syphillis/lupus/other spirochetal disease(Lapcorp report uses this spirochetal terminology and other infections as possible cross reaction in Lyme test)  etc.  In any case, thank you for your below clarifications!

Yes I will be following up with infectious disease expert soon (as well as an ortho, as this all very well could just be injury related).  Doxycycline was prescribed by general practician following equivocal Lyme result just to be cautious.  Happy to hear it works for syphilis too though!

My prolonged head pain had me concerned with either early HIV or unknown late neurosyphilis from theoretically something years ago.   Understanding I took the HIV test early and will retake to be sure, but I’m logically not as concerned about that possibility at present.  The neurosyphilis has more of my preoccupation so if you can clarify below a bit further I’d greatly appreciate it:

1- my understanding with RPR is that it tests for both any past infections/antibodies as well as present active infections.  Is that correct?  If so, late neurosyphilis should not be a concern based on negative result, correct?

2-does the logic of your answer to my previous question #3 apply to RPR as well?  Meaning my “symptoms” simply are not neurosyphilis symptoms, as the antibodies would be active from true symptoms and have caused a positive RPR?

Thank you again.  This service you provide is incredible.

You can limit conflicting health information by restricting searching to professionally run or moderated websites, and especially avoiding those by and for people with the problem or at risk (like Reddit, for example).