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STDs (Expert Forum)
Confusiion over other IgM Herpes posts
Answered by
University of Washington
Seattle - WA
Welcome to the STD Forum, which is intended only for questions and support pertaining to sexually transmitted diseases other than HIV/AIDS, including chlamydia, gonorrhea, syphilis, human papillomavirus, genital warts, trichomonas, other vaginal infections, nongonoccal urethritis (NGU), cervicitis, molluscum contagiosum, chancroid, and pelvic inflammatory disease (PID). All questions will be answered by H. Hunter Handsfield, M.D. or Edward W Hook, MD.
Confusiion over other IgM Herpes posts
by Help-Concerned, Sep 20, 2006 12:00AM
Sorry to drag up a frequent topic but I'm confused by the many threads on IgM tests being worthless. I had thought this was because so many have HSV1 and the test is not type specific. Also because a lack of the IgM antibodies doesn't mean you don't have Herpes.
However in one thread you responded that you can't be positive for IgM and not have either strain. So does this mean that when you say the test has a high incident of false positives that its because many have HSV1? Or because the test is often falsely positive for some other reason? If its not due to some other reason then I'm confused by the posts where people said their Herpeselect test were negative but IgM was positive and they were told they should disregard the IgM results.
In my case, I tested negative with Herpeselect a year or two ago and had been in a committed relationship for years. After a recent new encounter I was tested again ater 18 days with Herpselect (I know that is too soon for a new possible exposure). Still, it was negative for both types enforcing my earlier position that I didn't previously have either strain. However, an IgM test at 21 days was equivocal (1.01) so now I don't know what to make of it.
However in one thread you responded that you can't be positive for IgM and not have either strain. So does this mean that when you say the test has a high incident of false positives that its because many have HSV1? Or because the test is often falsely positive for some other reason? If its not due to some other reason then I'm confused by the posts where people said their Herpeselect test were negative but IgM was positive and they were told they should disregard the IgM results.
In my case, I tested negative with Herpeselect a year or two ago and had been in a committed relationship for years. After a recent new encounter I was tested again ater 18 days with Herpselect (I know that is too soon for a new possible exposure). Still, it was negative for both types enforcing my earlier position that I didn't previously have either strain. However, an IgM test at 21 days was equivocal (1.01) so now I don't know what to make of it.
Doctor's Answer
by H. Hunter Handsfield, M.D., Sep 20, 2006 12:00AM
, Sep 20, 2006 12:00AM
You're right, this has all been addressed several times. However, it's in many places and might be hard to dig out. So I appreciate the opportunity to put it all in one place.
In theory, the body produces immunoglobulin M (IgM) antibodies first, to a variety of infections, and immunoglobuin G (IgG) antibodies later. Over time, IgM antibodies tend to stop being produced entirely. Therefore, a test for IgM antibody to any particular infection may be positive before a test that detects IgG antibody. And in a person infected a long time previously, IgM antibody is absent but IgG persists.
That's the theory. In general, it holds up pretty well in young children, but sometimes not so well in adults. In adults with new HSV infection, IgM antibody against the virus doesn't actually get produced all that much faster than IgG antibody. And many people with longstanding HSV-1 or HSV-2 infection continue to produce IgM, especially when they have a new symptomatic outbreak. Thus, for HSV, IgM doesn't necessarily mean a new infection; and absence of IgM doesn't necessarily mean a longstanding infection.
On top of that, there are 2 other main problems with IgM testing for HSV. First, false positive tests are common--that is, apparent IgM antibody that simply isn't present at all, despite what the test says. This is NOT generally due to cross reaction with related viruses, i.e. HSV-1, varicella (herpes) zoster, and the like. It has to do mostly with the physical chemistry of the test.
Second, there are no type-specific IgM tests on the market--nary a one. Any true-positive IgM test for HSV is detecting antibody to HSV-1, HSV-2, or both, and can never distinguish between them.
Why do labs continue to offer such a lousy test? Several reasons there too, some reasonable, some not. Some providers still request the test; they were taught the theory, they assume it applies accurate to HSV, and don't understand the limitations of the test. (The pediatricians generally are right; IgM testing for HSV in fact remains useful in diagnosing neonatal herpes in newborns. Their immature immune systems don't crank out IgG so rapidly.) Also, some labs just keep offering the test out of habit, in the belief the providers want the test; while at the same time, the docs just assume that if the lab does the test, it must be worthwhile. (That is, a communication issue.) Also, there is simple profit motive for labs: IgM testing is very cheap but gets good pay-off from insurance companies, so the profit margin is high.
Bottom lines: Sometimes a new HSV infection in an adult indeed will be positive by IgM before IgG. But this is pretty infrequent, and it outweighed by the downsides: high risk of false positive result; and even when truly positive, there is no distinction between HSV-1 and HSV-2, which is pretty important to most patients and providers.
In response to your question, I re-contacted the people I know at Quest Laboratories. As of last month, as a matter of policy, Quest no longer does IgM testing for HSV in adults unless the provider specifically requests it. (Some individual labs might not have gotten the word yet, so some IgM testing might be done for a while.) Quest will continue to to IgM testing routinely for HSV antibody requests in newborn.
And do the bottom line for your particular situation: Totally ignore your recent IgM result with an equivocal outcome. Almost certainly it is meaningless. If you remain concerned, have an IgG test (and only IgG) 3 months after your last possible exposure.
I hope this helps. I have a feeling I will be referring future questioners to this thread quite frequently.
HHH, MD
In theory, the body produces immunoglobulin M (IgM) antibodies first, to a variety of infections, and immunoglobuin G (IgG) antibodies later. Over time, IgM antibodies tend to stop being produced entirely. Therefore, a test for IgM antibody to any particular infection may be positive before a test that detects IgG antibody. And in a person infected a long time previously, IgM antibody is absent but IgG persists.
That's the theory. In general, it holds up pretty well in young children, but sometimes not so well in adults. In adults with new HSV infection, IgM antibody against the virus doesn't actually get produced all that much faster than IgG antibody. And many people with longstanding HSV-1 or HSV-2 infection continue to produce IgM, especially when they have a new symptomatic outbreak. Thus, for HSV, IgM doesn't necessarily mean a new infection; and absence of IgM doesn't necessarily mean a longstanding infection.
On top of that, there are 2 other main problems with IgM testing for HSV. First, false positive tests are common--that is, apparent IgM antibody that simply isn't present at all, despite what the test says. This is NOT generally due to cross reaction with related viruses, i.e. HSV-1, varicella (herpes) zoster, and the like. It has to do mostly with the physical chemistry of the test.
Second, there are no type-specific IgM tests on the market--nary a one. Any true-positive IgM test for HSV is detecting antibody to HSV-1, HSV-2, or both, and can never distinguish between them.
Why do labs continue to offer such a lousy test? Several reasons there too, some reasonable, some not. Some providers still request the test; they were taught the theory, they assume it applies accurate to HSV, and don't understand the limitations of the test. (The pediatricians generally are right; IgM testing for HSV in fact remains useful in diagnosing neonatal herpes in newborns. Their immature immune systems don't crank out IgG so rapidly.) Also, some labs just keep offering the test out of habit, in the belief the providers want the test; while at the same time, the docs just assume that if the lab does the test, it must be worthwhile. (That is, a communication issue.) Also, there is simple profit motive for labs: IgM testing is very cheap but gets good pay-off from insurance companies, so the profit margin is high.
Bottom lines: Sometimes a new HSV infection in an adult indeed will be positive by IgM before IgG. But this is pretty infrequent, and it outweighed by the downsides: high risk of false positive result; and even when truly positive, there is no distinction between HSV-1 and HSV-2, which is pretty important to most patients and providers.
In response to your question, I re-contacted the people I know at Quest Laboratories. As of last month, as a matter of policy, Quest no longer does IgM testing for HSV in adults unless the provider specifically requests it. (Some individual labs might not have gotten the word yet, so some IgM testing might be done for a while.) Quest will continue to to IgM testing routinely for HSV antibody requests in newborn.
And do the bottom line for your particular situation: Totally ignore your recent IgM result with an equivocal outcome. Almost certainly it is meaningless. If you remain concerned, have an IgG test (and only IgG) 3 months after your last possible exposure.
I hope this helps. I have a feeling I will be referring future questioners to this thread quite frequently.
HHH, MD
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individuals can easily assume that if they didn't previously have any strain of HSV that a positive IgM test was a sure bet they had just contracted one of them. This misunderstanding is compounded by a lot of print saying false positives for Herpes almost never occur without specifying which "test" that statement was referring to. While a bit hard to find, you can see from this forum that there are actually quite a few incidents of false positives for people who do not have HSV with the IgM test and from your comments it sounds like even a lot more clinical data supports this as well that isn't so readily available to the public.
I believe another point to make is that equivocal test results means you can't tell either way. I think many assume (or worry) that this indicates they tested just a bit too early or too late and that the result will surely become positive as time goes by. Perhaps, but correct me if I'm wrong, if there was any statistical data supporting this notion to any degree I wouldn't think the result would be equivocal by definition. It doesn't help that I found a lot of contradicting information as to when the IgM test would be most reliable in the first place. Some said any time less than four weeks, another said 2-3 weeks dropping off sharply after that, and one provider of this test said 3-5 weeks. Being at three weeks for my test, I know that was my first thought since I was on the early side according to one reference and on the late side according to another.
Finally thanks for emphasizing that cross reaction is not generally a cause for false positives. For the information I did find through Google on IgM false postivies, this was pretty much the only explanation. Thus again easily causing people to worry that they either had one of these other conditions or that they truly did have HSV because they knew they didn't.
Since I misspelled confusion with a double 'i' it should be easy to reference through a search. <smile>
Correct me if I am wrong, but I think there is one instance when the IgM test is accurate.
If one performs a non-type specific test for HSV for IgM and IgG, the results are negative (and very accurate) if both results are negative.
Thanks for your feedback.
For the case you mention, while I'm not an expert, I don't recall seeing anything saying a non-type specific IgG test was more reliable than a type specific IgG test. If anything it was the other way around meaning that the Western Blot followed by the Herpeselect test are the two most accurate and fastest tests for adulsts as far as I'm aware. So what I'm suggesting is that one of these tests will be better in all cases over a non-type specific IgG test.
For recent exposure, having one of these tests done will reliablity tell you if you had HSV before the recent encounter (assuming enough time had passed between the two). This was my case, I knew I didn't have either strain before. So the only benefit of doing the IgG test with an IgM test is to rule out the possiblity that a positive IgM result wasn't due to a prior infection as opposed to a new one. If the IgM test came up negative, I don't see how it would be any more reliable with an IgG test (type or non-type specific) as in your example than by itself. And as already pointed out, the IgM is not reliable. I ran my test because I thought it might bring some anxiety relief until I could be IgG tested later. And sure if I had gotten a negative result I probably would have been relieved. However, because false postives can be so common, as I'm gathering from this group, my line of thinking didn't make any sense. The inconclusive result I got left me feeling the same and a positive result would have been devastating even though it shouldn't have since there is a good chance statistically (as I'm gathering from this group) that the result would have been a false-positive and how do you know the difference? Regardless, people don't think logically so they'll do the test anyway when it probably has a better chance of making them worry more than helping.
If you were talking long term exposure, your IgM level should disappear over time and the IgM test would be negative even if you have HSV (although it "can" rise again during an outbreak). So the accuracy of the [IgM + non-type specific IgG test] would be not really be more reliable than just the IgG test by itself.
Hope this helps!
As you probally are well aware of by now, their are numerous threads where people have positive IgM test but negative for both HSV-1 and HSV-2 on the IgG test. That is why IgM test are described as "worthless". Whether negative, equivocal or positive the test should be totally disregarded. It is possible for some with one or both strains of the virus to have a negative IgM and someone with niether HSV-1 or HSV-2 to have a positive IgM.
As far as the non specific IgG test, they are reliable only when negative. As you know, the older non specific IgG test detect antibodies for both HSV-1 and HSV-2 but can not tell you which strain you have. It can only tell you if you have HSV antibodies in your blood. If positive, it means you either have HSV-1, HSV-2 or both. Since most people want to know what strain it is they have, these test are not reccommended. Their are atleast 7 different type of antibodies your body will produce for HSV. The type specific Herpesselect test look for 1 antibody protein, that is "glycoprotein G"(gG-1 for HSV-1, gG-2 for HSV-2). This is the antibody the actually "surronds" or "envelopes" the outside of the HSV virus. The Herpeselect test can differentiate between HSV-1 or HSV-2 when this antibody protein is tested for. Thats why it is type specific. I hope this makes sense.
I am trying to understand for myself. I am devestated by my news, and want to get re-tested to confirm. I know it will be the same. My dr. did not show me the same type of results. My test were done by Lab Core.
Thank you very much for any help someone can provide.
I understand how devastated you might feel. If you read this forum, you'll find out that you certainly would not be alone if you did have HSV 2 and the majority of people have HSV 1. You shouldn't feel horrible about yourself but if you do support groups will be very helpful.
Note, your question is really a new thread. If you still have questions submit them as a new post and I'm sure the doctor will be happy to help. Don't be surpised though if he doesn't have much to add other than what you can already find by searching the previous posts. At this point, assuming you are positive, counseling for how to cope and for direction would seem like the best thing thing for you to do. Forget your ex...
Good Luck!
To make sure I am clear, we had been seeing each other for over a year, so I dont know how long I have had it. However, shouldnt he have it sense I do not have to get an outbreak to transmit?
What you are saying is that the nonspe. test haveing high levels is not a concern. If his specific test is negative, then he does not have it and should get retested.
All of this is very new to me, and I have read so much information that I get more confused. Wow, I made the assumption that he gave this to me, and now I know it is the other way around. You are right, I do feel nasty.
I am going to the dr. on Monday for re-test. I will let you know how it turns out. THANK YOU very much for replying. I feel very alone in this as none of my friends know.
Regarding my previous response, I wasn't saying a non-specific test is not a concern. What I was saying is he has one test that says he has either HSV1 or HSV2 and another test saying he has neither. Both can't be right. I then was saying the Type specific HerpeSelect test is the best test to use for general testing. So if I had to pick the results of one or the other I would go with the HerpesSelect results. Non-type specific tests typically are older technology and more prone to false results.
As for who gave it to who, you probably will never know unless after five or so months since your positive test he is still negative. In which case, you almost certainly did not get it from him. He still may have it as it can take up to three months but rarely up to five or so months from your last sexual encounter together to test positive even with the HerpeSelect. To make this a little easier to understand, let's say you both contracted it on the same day. He might test positive in four weeks or less while it might take you three months. So you just don't know who had it first unless there was enough time (3-5 months) between one of you testing positive and the other negative.
As I said earlier, don't feel bad about yourself. There are people from all walks of life that have Gential Herpes...rich, poor, famous, beautiful, smart, etc... The disease does not define you as a person. Statistically some of your friends have the disease as well and obviously someone you knew if not your ex gave it to you as well. No one wants to hear they have Herpes but really the psychological burden is much worse than the disease itself. If your friends can't be supportive then they're not real friends. Then again unless you're sleeping with them there's no reason to tell them either. Just don't keep it all bottled up inside. Find a support group or someone you can confide in; friend or otherwise. As a related note, a good friend of mine told me she was HSV2 positive years ago, long before I knew anything about the disease and we're still good friends and she's a wonderful person.
I wish you all the best.