[Question #2412] Follow up to Question 2407

45 months ago
I am a little confused about the right test to take. I noticed that an earlier thread mentioned that the 4th generation tested looked for the p24 antigen, but in the test description (link below) I didn't see any reference to it. Can you please confirm this is the correct HIV 4th generation test for me to take, or is there another one that's more appropriate/accurate? 


https://www.labcorp.com/test-menu/28801/human-immunodeficiency-virus-1-o-2-hiv-1-o-2-antigen-antibody-fourth-generation-preliminary-test-with-cascade-reflex-to-supplementary-testing
H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
45 months ago
It says "antigen-antibody-fourth-generation". (p24 is the only "antigen" in all such tests.) No need to worry about which 4th gen test is offered; all are equally reliable after 6 weeks.

HHH, MD

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45 months ago
Hello Doctor, the 4th generation test came back negative. For piece of mind I also want to get the herpes IGG test as this morning I noticed what appears to be a bug bite on my testicle. I actually saw a tiny red speck at the itching site, and it came off. I couldn't locate it afterwards, but I think it was a chigger.

I'm wondering if there's a herpes test that will actually give me a value that's less than .91? I took two before at 4 weeks and 6 weeks and both came back negative. I asked the testing company if I could get a value and they said they don't have them if they're lower than .91, but from reading others questions, it looks as though that's not the case. They said if I took a PCR test they would be able to give me a value. Is that correct? Given my situation and previous question (2407) does this seem like this herpes to you?  At 8 weeks post exposure, what are the chances a positive result will show up on an IGG test? The red spot that itches doesn't have any blisters or open lesion, just looks like a regular bug bite.

Thanks for your response.
45 months ago
One more thing - I had a similar bump a few weeks ago, right around 5 weeks post exposure, but not as much itch. I had bites all over my legs and a few in my pubic region which didn't seem abnormal, given the other bites. I saw my dermatologist and he said he was certain it wasn't herpes. He also did a swab which turned out negative, but it was 4 days after the bump appeared so I'm not sure it would've shown up on the test anyways. A few days later I applied neopsorin to the bump on my testicle and it became much worse. I saw my dermatologist again and he said it was an allergic reaction to neopsorin and gave me topical steroid which cleared it up. 

I saw my dermatologist again today and he gave me a PCR swab upon my request and another regular swab. My question is would these tests be accurate if this is actually a second outbreak?  Sorry for the long-winded question, I just want you to have all the facts. Thanks again.
H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
45 months ago
Based on the information you have provided, including your symptoms, test results to date, and the low risk of the exposure several weeks ago, you can be sure you do not have genital herpes. There is no reason for a lab to provide HSV2 numerical results below the negative cut-off of 0.9, even though some labs do so. There is no difference in meaning or interpration in different numbers below 0.9. Even the same specimen tested repeatedly will often give results that might vary from 0.2 to 0.5 to 0.8 and back to 0.3. All are equally negative. In any case, from all you say, I'm confident that any and all additional HSV tests you have will remain negative.

As for PCR testing, it made no sense in this situation. Herpes is an intermittently active disease. When active, a minority of the time, PCR will usually be positive, but a negative result is never conclusive evidence against herpes. I'm sorry your doctor went along with your insistance in that test:  in our clinic, we would not have done it regardless of your pleading.

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44 months ago
Thank you for your response Dr. Handsfield. I guess I was misinformed. I thought that when a symtom appeared, which is the case for me right now, getting the symtom swabbed is best way for a diagnosis. If this red bump is in fact herpes, do you think it's likely the PCR test will pick it up? 

I know you said you think that any future test will be negative, but do you see any point in me doing another IGG test since I do have a symptom? Like I said, I think it's a bug bite but I just want to be as sure as possible.  Thanks again for your input and advice.
H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
44 months ago
PCR is most likely to be positive if there is a fresh blister or pustule. A "red bump" could be herpes but have a negative result. With your penile bump almost certainly the same process as your other apparent insect bites, and the low risk of your exposure, herpes is vanishingly unlikely. I would never have done IgG testing in this situation and see no medical need for further testing. OTOH, since you have started down that path, I would understand that you might want to have a final test after 16 weeks, which is the time it sometimes takes for HSV2 antibody to become detectable. If so, feel free. If you do ti, you can expect another negative result.

I think the main problem you have is emotional adjustment to a sexual decision you regret. Try to separate those concerns from disease risk from the event:  they aren't the same. Deal with the former as you need to (counseling?), but do your best to disregard the latter.

That completes two threads on this exposure, symptoms, testing, etc. The forum does not permit repeated questions on the same topic or exposure. This will have to be your last one; future new questions about this exposure, testing, and your fears about HIV, herpes or other STDs will be deleted without reply and without refund of the posting fee. This policy is based on compassion, not criticism, and is designed to reduce temptations to keep paying for questions with obvious answers. In addition, experience shows that continued answers tend to prolong users' anxieties rather than reducing them. Finally, such questions have little educational value for other users, one of the forum's main purposes. I trust you will understand.

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