[Question #9687] False Negative Tests
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30 months ago
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Hello doctors. 11 months ago a had a high risk encounter with a street prostitute. Not a "fancy" high paid CSW but one from the streets (thats why I consider it high risk). The whole encounter was protected, she performed oral job on me with condom and then we had vaginal sex with condom. The condom was provided from a hotel lobby so I really dont know the kind of condom or the expiration date.
Ive had 2 negative urethral swab test performed at 2 and 4 months post exposure and 1 negative urine test at 7 months post exposure. All these for chlamydia, gono and some other bacteria.
Ever since the exposure Ive been having some discomfort around my penis and testicles, main symptoms lingering to this day are:
- Penis pain (mainly on tip)
- Testicular pain
- Groin pain
- Some redness on penis head
- Low ejaculation strength
I was diagnosed with prostatitis after a DRE my urologist did and it was treated. Few months after Ive had a few more DRE and doctor says prostate is normal, but all my symptoms are still there. Ive had double contrasted abdominal and pelvic tomography and nothing shows there. Also some pelvic abdominal ultrasound and nothing there. None of my studies show anything so I wonder if this could be a missing infection?
1) Could I be experiencing a false negative test result or missing infection? My tests also looked for mycoplasma and ureplasma and other bacteria. All negative
2) In false negative tests, how do doctors determine it was false negative and give treatment?
3) Is there anything else I should be looking for?
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Edward W. Hook M.D.
30 months ago
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Welcome to our Forum and thanks for your questions. FYI, I happened to be on the site when your question arrived so you are receiving my response more quickly than is the norm. Follow-ups may take longer. Before I address your specific questions, let me provide some general facts:
1. Despite the relatively higher risk of the encounter you describe, most commercial sex workers do not have STIs.
2. When one has a sexual encounter with an infected person, even an unprotected encounter (which was not the case for you), the majority of exposures DO NOT result in infection.
3. Condoms, when used throughout an encounter and when they do not break (as happened about 1% of the time) are excellent protection against STIs. When condoms do fail, it is obvious- they break wide open.
Now, on to your situation: The symptoms you describe are not typical symptoms of STIs. The redness and discomfort on the head of your penis may be related. If the redness is persistent, a dermatologist may be helpful as most genital rashes are due to something other than STIs. Also, I presume the urologist has examined you while you were experiencing testicular pain - if an STI were present he/she would had noted an abnormality.
I doubt that an infection is being missed. Current tests for the most common STIs are amongst the most sensitive tests in all of medicine. That, combined with your repeated exams by a trained professional (your urologist) make it most unlikely this is an STI which is being missed. I wonder if your continuing symptoms could be residua of your prostate infection:
In answer to your specific questions:
1) Could I be experiencing a false negative test result or missing infection? My tests also looked for mycoplasma and ureplasma and other bacteria. All negative
Unlikely that anything is being missed her
2) In false negative tests, how do doctors determine it was false negative and give treatment?
False negative tests are detected in several ways- through repeat tests as many causes of false negatives are transient, or when symptoms are present, the fact that symptoms are present but tests are negative. In your case however, your symptoms really do not suggest an STI.
3) Is there anything else I should be looking for?
As I said above, this discomfort may be residual from your prostatitis. In some instances, due to lingering scarring, etc. symptoms may persist for a prolonged period.
I hope that this perspective is helpful to you. EWH
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30 months ago
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Thanks doctor.
You are right, Ive seen two different urologists and none has found any abnormalities in my penis and/or testicles.
I think I should clarify that this prostatitis was diagnosed and treated 7 months ago and theres really nothing show up at this moment either via DRE or imaging studies so my doctor really feel this is nothing to do with prostate.
- Do you think I should retest for Clhamydia and Gono to be sure of this transient causes of false negative?
I often have other symptoms like discomfort after ejaculating
- The condom I used didnt break (at least not in an obvious way). What would you think would be my overall risk?
The redness on the tip of my penis is not persistent, it comes and goes, and often looks like is just full of blood circulating. Do you think this could be related to STI?
My main concern is because Ive read that infections like clhamydia, when unattended, can lead to pelvic pains and testicular pain and this is all too coincidencial. Hope you understand
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Edward W. Hook M.D.
30 months ago
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Straight to your follow-up questions:
Perhaps I was not clear. While the bacterial causes of prostatitis and related inflammation can be cured or subside, the process may leave scarring behind, which can potentially cause testicular symptoms or difficulty with urination.
Repeat testing it’s a personal choice. If you choose to test again, I anticipate that the results will once again be negative. Please remember, for all the reasons I mentioned above, this encounter was actually low risk, despite the nature of your partner.
There are no STI’s which causes pain on ejaculation.
I would classify this encounter as low risk for all of the reasons that I have cited above.
I sincerely doubt that the symptoms you’re experiencing represented STI. Please understand that sometimes when individuals become concerned after an encounter, they wish they had not had. There’s a tendency to search and look for signs and symptoms of infection would otherwise go unnoticed. I can’t help but wonder if this is at least a contributor to your difficulties. EWH
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30 months ago
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Thanks.
1- In case I was actually exposed to Chlamydia or Gono 11 months ago, do you believe my immune system would have cleared it up by now? I found this answer from Dr Handsfield on question #8579 on this forum: "The immune system indeed clears urethral gonorrhea, chlamydia, or NGU, but not so quickly: typically several weeks for gonorrhea, several months for chlamydia. NGU unknown, but surely 1-2 weeks is much too soon." And Ive read similar answers in other questions. Do you think that in case I was exposed I would already be cured?
2- 4 months after the encounter I took 1gram of Azithromycin (for something else). I must say it was not Zithromax, it was some generic brand with 2 500mg pills (I don't know if that makes a difference). Would this have cured Chlamydia if I had it?
3- When I took the urine sample it was a first void sample in the morning as suggested by the lab, but they didnt tell me anyting about the amount of urine I was to collect. I took a whole sample (those cups that the labs give you) and when I was looking online I found out that the recommended amount for this test is 20-30ml and that a larger sample may dilute the sample making the test less sensitive. What do you think about this?
4) 10 months after the encounter I took HIV Ag/Ab test and was negative. A few weeks ago (after the test) I experienced one of my worst flu ever with extreme headache. Do you think Im on the clear or should I test again? Could this be antibody formation just now or my body acting out to HIV?
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30 months ago
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The standard size of a lab cup can hold aprox 120ml so I gave a lot more of a sample than the suggested amount. I dont know why the lab didnt tell me this.
Also I was taking tadalafil at the time of the test (to treat the prostaitis) could this interfere with the test?
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Edward W. Hook M.D.
30 months ago
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As you know, we provide up to three responses to each clients question. This is my third response and so this thread will be closed shortly after completion of this response. It appears that you were going down a “what if” rabbit hole. Please believe your test results and that you were not infected. It is simply not healthy to be worrying the way you are. In response to your specific questions:
1. The figure that Dr. Handsfield mentioned it’s based in part on research which I have performed. Indeed, the immune response does clear, chlamydia and gonococcal infections without treatment in many asymptomaticly patients over a period of weeks following infection. In the unlikely event that you were infected, it have well cleared by now. However a far more likely possibility, however, is that you were never infected to begin with.
2. Yes, 2.5 g of azithromycin, including the generic variety, would’ve cured chlamydia and well over 60% of gonococcal infections if you have been infected.
3. The dilution factor would have no appreciable effect on the accuracy of your test results.
4. You were 10 with HIV test results are absolutely conclusive and should be believed. There is no medical or scientific reason for repeat testing related to the encounter. You are concerned about.
There are no medications other than antibiotics which would affect the accuracy of your tests for Gonorrhea or chlamydia.
As this is my final response, let me repeat that I sincerely believe that you are overthinking this. Sometimes guilt and anxiety are powerful forces with your hard to shake. If you continue to have the level of concern that you expressed in this thread, I urge you to consider seeking the input of a trained mental health professional for tips on how to move forward from your concerns. I say this out of concern for you, nothing more. Please don’t worry. Take care. EWH.
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