Lingering doubt

[Doglover55]

Hello Drs.
Thank you for providing a place for expert advice. I have read many of your posts and while they have brought me some solace I suppose I need an answer to my specific situation to put my mind at ease.

I am female and made a poor decision to engage in activity with a man of unknown status. We had what I believe is called frottage, rubbing around on outside of genitals, but he did insert into my vagina on three separate times. I made him pull out, no pumping or ejaculation. Then we switched to oral sex, me both receiving and performing. He did ejaculate then and while I tried to pull away I believe I could have been exposed to semen.

I had all std tests done as early as allowed, all negative. My GP wanted to wait until 12 weeks to do hiv tests, but my anxiety wouldn't allow. 4th gen tests at 53 and 67 days, both negative. She says I was low risk and this is conclusive. She wanted to wait 12 weeks originally so not sure of change in opinion.

Questions
1. Low risk? Hiv is present in precum so isn't it possible to contract in my case?
2. Regardless of risk are my tests at those times conclusive?
3. This test is conclusive at 28 days in parts of UK. Does it become less accurate the longer you wait? Essentially does P24 antigen drop off after that time and if it does would antibodies always be detectable? Is this test more sensitive to antibodies than 3rd gen and that's why it can be conclusive earlier than them?
4. Why does the CDC insist upon the 12 week? I feel like it is the only thing holding me back from moving on. I've read so many expert opinions about earlier window period yet the 12 week thing is an unwelcome little nag in the corner of my thoughts.
5. Any chance at all that an almost 10 week negative 4th gen test would turn positive 17 days later?! Ever seen a case like that?

Thank you in advance, I appreciate your time in response.
Lucy

[Edward W Hook, MD]

Welcome to our Forum. I'll be pleased to address your questions.  The exposure you describe is low risk for HIV.  The reason for this are several and include that few men have HIV (about 1%) with the rates among heterosexual, non-IV drug users being far lower (more on the order of 1 in 10,000).  When this, along with the low risk for infection following any single exposure are considered, your aggregate risk for infection was less than 1 in a million before testing and with testing is far lower than that.  These estimates are related to the facts that HIV is rare among heterosexual men (see above) and that following penetrative vaginal sex the risk for infection is one infection per 1000-2000 sexual encounters (and in your case is lower still given the limited nature of your penetration).  The risk from either giving or receiving oral sex is at least 10 times lower than for genital exposure and thus even less of a concern.  Putting all of this together, I feel you can be entirely confident that you did not get HIV from the exposure you describe.  

Regarding your specific questions:
1. Low risk? Hiv is present in precum so isn't it possible to contract in my case?

Yes, HIV is present in pre-ejaculatory fluid.  Nonetheless, as explained above, your risk is quite low.

2. Regardless of risk are my tests at those times conclusive?

Yes, 4th generation tests are conclusive at any time more than 28 days after exposure- you've been tested twice.  These are conclusive results and your doctor is being overly conservative.

3. This test is conclusive at 28 days in parts of UK. Does it become less accurate the longer you wait? Essentially does P24 antigen drop off after that time and if it does would antibodies always be detectable? Is this test more sensitive to antibodies than 3rd gen and that's why it can be conclusive earlier than them?

No, accuracy does not change over time because as the sensitivity of the p24 antigen test declines with time, the sensitivity of the antibody test increases to nearly 100% at the same time.
.
4. Why does the CDC insist upon the 12 week? I feel like it is the only thing holding me back from moving on. I've read so many expert opinions about earlier window period yet the 12 week thing is an unwelcome little nag in the corner of my thoughts.

The CDC's estimates are constrained by policy and a belief that they cannot "afford" to be wrong- hence they use older, out of date recommendations.  

5. Any chance at all that an almost 10 week negative 4th gen test would turn positive 17 days later?! Ever seen a case like that?

Have never seen such a case and urge you not to worry at all about it.

I hope these comments are helpful. EWH

[Edward W Hook, MD]

Final answer. The rash ("zits") you describe are not suggestive of HIV.  (Past) time to move on. EWH

[Doglover55]

Dr. Hook,
Lately I've been noticing an increase in zits. On my face and chest. This isn't anything that should make me doubt my results? I treated them with benzoyl peroxide, but then developed little red itchy bumps on my neck. Is this all anxiety?! I'm being ridiculous, right? Why is it so hard to move on?

[Edward W Hook, MD]

Glad I could help.  Take care. EWH

[Doglover55]

Thank you again. Being in my line of work probably isn't helpful when combined with my inherited anxiety. Also just so mad at myself for even putting myself in a position to be at risk. Time to move on, I know. Thanks for your advice. Good night.

[Edward W Hook, MD]

Please don't worry.  Lab errors of the sort you mention can be a problem however the likelyhood of you have two such errors a week apart is negligible. With two negative tests at the times you had them, you can be confiden tthat you did not get HIV. EWH

[Doglover55]

Hello again Dr. Hook,

So I was doing pretty well with accepting my results as conclusive until today. I'm a nurse and I'm sure this is what fuels my pessimism and worry. We had a patient who had a lab error today, mind you it wasn't hiv, but it did set off a worry in my head that I can't seem to fight off on my own. My negative duo tests at 8 and almost 10, no chance of false negatives at those points? I'm negative without any doubt?!

[Edward W Hook, MD]

Glad to help. EWH

[Doglover55]

Thank you so much!

[Edward W Hook, MD]

No, neither of these drugs, nor your Hashimoto's will effect your test results. EWH

[Doglover55]

Thank you! Your answers are just what I needed. I know I has read somewhere on a post here, but I have Hashimotos and take Armour and Cytomel. Those do no affect these results?