[Question #12450] STI Testing Conclusivity

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7 months ago
Hello. 

16 weeks ago, I received oral sex from someone I didn't know. This consisted of a bj for approximately 90 seconds. No other sexual contact occurred.

Since this event, I have undertaken STI panels which covered RT-PCR urine tests for Chlamydia and Gonorrhoeae, antibody tests for Hep C and syphilis, antigen/antibody testing for HIV, antigen test for Hep B and IGg and IGm testing for HSV1 and 2. I've returned clear panels as above at 2, 4, 7, 10, 13 and 16 weeks after the event. 

I was examined a number of times by two doctors and other than a slight case of possible thrush which has long cleared up with some cream, they could not find anything in terms of symptoms (blisters, chancre etc). I would also consider myself asymptomatic.

Can I consider my results to be conclusive? My particular fear is HSV but I've now returned 6 normal results for this. Unfortunately, I read online that 16 weeks is conclusive but also places suggesting 6 months is needed. Am I being completely ridiculous? When can I go back to having sex with my partner?

Thank you in advance.
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Edward W. Hook M.D.
7 months ago
Welcome to our Forum and thanks for your questions.  I’ll be glad to comment.  You have tested far more than you need to to prove that you were not infected by the very low risk exposure you describe.  Few STIs are transmitted through receipt of oral sex. There are no proven instances in which someone has gotten HIV from receiving oral sex and even when partners have oral STIs, most single exposures do not result in infection.  HSV-2 is almost never acquired from receipt of oral sex.

If a person chooses to test as you have, tests for gonorrhea and chlamydia are entirely conclusive 3-5 days after exposure and blood tests for HIV, syphilis, and hepatitis B  are conclusive at 6 weeks.  Blood tests for HSV are notoriously unreliable and are not recommended.  You are fortunate that you have not had a falsely positive herpes blood tests.

At this point I would encourage you to stop testing and move forward.  It’s time.  There is certainly no reason to avoid unprotected sex with your regular partner related to the encounter you describe.  EWH

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7 months ago
Thank you for your swift reply, Dr.

Just to follow up, and I'll try not to be repetitive:

1. I read here on some other questions that herpes transmission is probably lower than 1/1000 due to penetrative sex with a partner who is infected. Given that transmission from oral sex is far lower, and that I have no specific reason to believe the person had herpes, my chances here are probably astronomically in my favour. Would that be a fair assessment?

2. HSV blood testing was the only option available to me as I had no sores or symptoms to swab. Is the main issue with blood testing, the risk of false positives? Is there any reliable data regarding patients who develop antibodies after testing negative after 16 weeks? Most places seem to consider 16 weeks conclusive. 

3. I expect it's not a major risk, but is Hep C conclusive at this point? There was no blood etc involved.

Apologies if my questions are somewhat neurotic. Medical anxiety is new to me and I'm mostly concerned with the health of my partner. 

Thank you
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Edward W. Hook M.D.
7 months ago
In reply

1. Correct
2. Blood tests can also be falsely negative or confuse HSV-1 for HSV-2.  In general they are crummy tests.  There are few if any good data on persons becoming positive after 16 weeks.
3.  Hepatitis C is not an STI with the rare exception of persons practicing recptive rectal intercourse.  Even then if is quite rare.


I really thin you are worrying entirely too much.  Again, I encourage you to take a deep breath and relax.  You have one follow-up remaining.  EWH
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7 months ago
Thank you Dr 

Anxiety is tough but I will certainly do my best to take on board and fully accept all you have said. If you happen to have any other words of advice or reassurance, they'd definitely be welcome. Otherwise, thank you again for responding to my message, your reply has helped a great deal.

Thanks again

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Edward W. Hook M.D.
7 months ago
Anxiety is often also enhanced by guilt.  That said, I remain confident that you do not have an STI.  Believe your test results.  The tests you have had are very reliable and repeated tests giving the same negative result should be believe.

Closing the thread now.  Take care.  EWH
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