[Question #4693] STD Testing Accuracy at 12 Weeks

26 months ago
Hello Doctors,
I have a question on STD testing. About 3 months ago I received oral sex from someone whom I do not know the STD status of. I had a full STD test performed 7 days after this incident. All tests with the exception of HSV IGM 1/2 were negative. The HSV IGM 1/2 came back as 1.6. I have been extremely worried since then, and had STD tests performed at 21 days, 64 days and 81 days. All tests, including HSV IGG Type Specific and HSV IGM 1/2, came back as negative. However, at about the same time as the last test, day 81, I noticed a raised bump behind the foreskin of my penis. The bump is not filled with fluid, does not hurt when I touch, no pain when urinating, and has remained unchanged for about 3 weeks now. I did not experience any flu like symptoms in the past 3 months either. I have had no sexual relations since this incident. Is it possible that this bump is herpes, and all the tests I have had so far are false negatives? Are there further tests that I can perform? Is the Western Blot herpes test available in New York? Do you recommend any other way to confirm if this is herpes or not? 
H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
26 months ago
Welcome to the forum. Thanks for your confidence in our services.

Oral sex is very safe, with low risk for all STDs and zero (for practical purposes) for some. Also, 7 days is fine for a urine or swab for gonorrhea/chlamydia, but far too soon for all blood tests. In addition, the news about herpes is good:  your later tests are strong indications you do NOT have HSV, either HSV1 or HSV2.

STD and herpes experts never, ever request IgM testing, because we know the results are always unreliable. In theory, IgM antibody appears early, later replaced by IgG, and thefore postiive IgM with negative IgG indicates a newly acquired infection. Unfortunately, that theoretical progressin doesn't work well for HSV antibody. In addition, IgM testing is very prone to false positive results. That's what's going on here, which is proved by your negative later IgG test results. And by the way, the positive IgM result at 7 days was too early, even for IgM testing. If that result really was from a new HSV infection, it would have been acquired 10-20 days before the test.

What to do now? Although your negative HSV IgG test at 81 days is nearly conclusive, sometimes it can take up to 16 weeks for a positive result. I am very confident you don't have it, based on lack of symptoms that suggest herpes, plus the negative results so far. However, in view of the positive IgM result, I imagine you're going to want absolute confirmation. If so, you could consider a final HSV 1/2 IgG test at 16 weeks. You can expect it to be negative. The only additional wrinkle is that your exposure was oral, which risks HSV1, not HSV2; and some people with HSV1 never develop positive IgG test results. However, these people often remain negative by Western blot as well, so that test wouldn't necessarily sort things out. But all things considered, the chance you have any new HSV infection is zero for practical purposes and if you were my patient (or someone personally close to me) I would recommend only the additional IgG test at 16 weeks and not Western blot, assuming the 16 week result also is negative.

Finally, a single genital area bump like you describe doesn't sound at all like herpes. HSV cannot cause a bump that doesn't change over 3 weeks. Conceivably a genital wart (?), although a single warts is uncommon -- usually several appear at once. Probably more likely a benign skin problem like a fibroma, sebaceous cyst, skin tag, etc. The only way to sort this out with certainty is to be professionally examined. But for sure it isn't herpes. 

Herpes questions normally are answered by Terri Warren, but I was well into this reply before I realized you're not much concerned about other STDs. So I'm letting it stand. However, I'm going to reassign this thread to Terri and ask her to weigh in. I'm pretty confident she'll confirm my opinions and advice. But let us know if anything isn't clear.

HHH, MD
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26 months ago
Thank you very much for your response Doctor, I really appreciate it. Just one more question - if the bump indeed is herpes, does it mean that my body has seroconverted and created antibodies that are detectable by the blood tests? Other words, is it possible to have symptoms and no detectable antibodies?
Thank you
H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
26 months ago
There is simply no possibility that bump is herpes.

Yes, it is possible to have herpes symptoms -- which you don't have -- and have no detectable antibody, especially for HSV1. It's not common, but it happens.
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26 months ago
Thank you for your responses Doctor Handsfield. I will get a final test at 16 weeks to be sure as you suggested. I have no more questions. 
Terri Warren, RN, Nurse Practitioner
Terri Warren, RN, Nurse Practitioner
26 months ago
Thank you Dr. Handsfield for answering this question.  I would certainly agree with most of what you've said here.  The HSV 1 thing is tricky - in a study looking at more than 700 patients we published two years ago, the IgG test missed 30% of HSV 1 infections, compared to the western blot.  Since we published that study, I have gathered date on over 500 more subjects and it continues to be the case that the HSV 1 IgG is quite insensitive compared to the western blot.  The University of Washington quotes the sensitivity of the HSV 1 western blot at 95-96%, which means it would pick up 95 or 96 cases of HSV 1 in 100 infected people, and this information came from them to me within the past 3 months.  Their current recommendation is to test at 12 weeks out from a concerning exposure (they used to say 16 weeks) but if you've taken much antiviral medicine (more than 2 weeks), it can influence the accuracy of the blot and you should wait a bit longer to do the test. I don't see that you've done that.  And if you want to wait until 16 weeks to test, there is certainly no downside to that!   If you decide that you want to do the blot in NY, I can facilitate that for you.  However, you need to be aware that if you do the blot and it is positive, it cannot tell you where you are infected, only that you are or are not (with 95-96% sensitivity).  As Dr. Handsfield told you so clearly, the IgM is awful.  In my experience, it is falsely positive 80-90% of the time - terrible test and the CDC says to never use it to try to diagnose genital herpes infections.  It's difficult for people who have tested positive on the IgM to let this go and they often worry for a long time, in spite of negative IgG tests and even western blots, that they are truly infected.  Please don't fall into that trap.  People who have this worry are vulnerable to being afraid.  The problem is that the IgM is not wrong 100% of the time so now that you've done it, you probably will want to follow up.  Such a bummer.

Terri
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26 months ago
Thank you for your response Terri. I would like to get some closure on this issue and would like to pursue the western blot as a last test if it can be a more conclusive test as you advise. Please advise on how I may schedule a western blot in New York. Thank you
Terri Warren, RN, Nurse Practitioner
Terri Warren, RN, Nurse Practitioner
26 months ago
You would need to set up a video conference with me first at www.westoverheights.com - there is  box on the home page that you can click to get into an app called evisit where you can set up that appointment.  I think I even have some open for this morning.

Terri
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H. Hunter Handsfield, MD
H. Hunter Handsfield, MD
26 months ago
That concludes this thread. I hope the discussion has been useful.---