[Question #3803] HIV ag/ab 4th gen

34 months ago
Hi - my ob-tested me at 11 days after exposure (negative) and the ER tested me 17 days after exposure (negative, not sure which test they used). Am I okay with these tests or would you retest at 28 days? Thank you so much, I really appreciate this forum.
H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
34 months ago
Welcome to the forum. Thanks for your confidence in our services.

Having read the forum, you may realize that we usually structure our advice about HIV or STD exposures and risk around substantial knowledge of the nature of the exposure so we can best judge the overall situation. Based on your tests alone, I can say that your first test wasn't very helpful:  around 30-40% of newly infected people might have positive results by 11 days, but a negative result doesn't man too much. At 17 days, probably 80-90% would be positive, so that negative result is quite reassuring. However, no Ag/Ab (4th generation) test is conclusive until 4 weeks or sometimes 6 weeks after exposure. So for final reassurance you likely will require at least one more test.

As implied above, I might be able to help more if you'd like to fill in some details. What do you know about your partner? HIV status or risks? Vaginal, anal, or oral sex? Condom? Where did this occur, geographically? I'd be happy to comment further if it would be helpful.  In the meantime, however, your tests strongly suggest (but do not yet prove) you didn't get HIV during that event.

I hope this information is helpful. Best wishes--   HHH, MD
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34 months ago
Hi - I am a female with exposure six times to a male with HSV2 but no other confirmed diseases. He lied about the HSV2 so now am scared what else he could have. No protection was used. I thought based on other replies the ag/ab (4th gen) was always conclusive at 4 weeks? Many thanks! 
34 months ago
Vaginal
Massachusetts
H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
34 months ago
Thanks for the additional information. Assuming your partner is not bisexual or an injection drug user, the likelihood he has HIV probably is under 1 chance in several thousand. I certainly understand your concern, however -- I'm not arguing you shouldn't be tested, only that you definitely can expect any additional HIV tests to remain negative. For final reassurance, I would recommend one more Ag/Ab test 6 weeks after your last exposure with this partner.

About a year ago, a comprehensive review of the performance of all available HIV tests (in the US) was published, which concluded that in rare cases the Ag/Ab tests require 6 weeks for conclusive results. At that time we revised our routine advice to 6 rather than 4 weeks.

You also should be tested for gonorrhea and chlamydia, if not yet done. Your risk for these STDs is far higher than for HIV. Also a syphilis blood test at 6 weeks, although syphilis is almost as unlikely as HIV in this situation.

Are you also following up on the HSV2 exposure? Being tested for it? You probably know that HSV2 infections often are asymptomatic, and many infected people don't know it. If your partner for sure knew he had it, of course he should have told you. But if only recently diagnosed, maybe he genuinely didn't know.

I hope these additional comments are helpful. Best wishes.
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34 months ago
Hi Dr. Handsfield,

I had a primary outbreak in early May and had a swab done of one of the lesions and it tested positive for HSV-2. I had had blood work done in mid-April (at my physical) and both HSV-1 and HSV-2 were negative.

This partner and one other recent partner were both tested in the past month and both came back negative for HSV-1 and HSV-2. I have had no other partners in years. It sounds like the virus can take 10-12 weeks to show up in blood tests. Would the most logical explanation be that one of these partners recently acquired this? I am so confused.
H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
34 months ago
It's often difficult to work out exactly when and from whom genital herpes is acquired. You obviously have HSV2, and almost certainly it was a primary infection -- evidenced by a negative HSV2 blood test in April followed by an outbreak in may with positive test for HSV2 from the lesion(s).

The puzzling part is that both potential source partners apparently tested negative for HSV2. It sounds like one of them also acquired his infection recently and transmitted the infection to you before his blood test became positive. He may or may not have known he had it -- in other words, perhaps had no obligation to tell you, since he wasn't aware he was infected.

I'm not sure how important it is to know exactly which of your two partners infected you. (It should be important to them, of course -- but perhaps not crucial for you personally.) But if either or both of them are concerned and cooperating, they should be retested a couple more times. You also could double check your own previous blood test result last April, to make sure there wasn't a reporting error.

My comments about testing for gonorrhea and chlamydia still stand. I hope that was done. For HIV, you should have a final Ag/Ab blood test 6 weeks after the last possible exposure. Newly acquired genital herpes significantly raises the risk of HIV, if sexually exposed to it. (It remains unlikely you caught HIV, but better safe than sorry!)

That concludes the two follow-up comments and replies included with each question, and so ends this thread. I hope the discussion has been helpful. If you would like further advice about your herpes, you could consider posting a new question in the herpes category.

Best wishes and stay safe--   HHH, MD

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