What is the normal amount of variability in IGG test results

[metsox]

I think this was probably just bad timing, but about 3 months ago I was spending a lot of time with a friend who said he was diagnosed with a primary genital herpes infection (don't know HSV1 or 2).  We had no physical contact and didn't share any utensils, towels, etc.  At around that same time, I started getting sores in my mouth.  They were never outside of my mouth, not painful, and seemed to me like canker sores- mostly by themselves, with a white inner circle, relatively small.  I had them pretty constantly over about a 3-4 week period.  Because of the timing, and because my wife is pregnant, I decided to be safe and get tested.  I have not experienced any other symptoms and have not seen any sores on my genitals.  

My doctor had both the IgM and IgG tests done.  They were done at QuestDiagnostics, so I believe the IgG tests were the HerpesSelect.  

I had 3 sets of tests:

1) After 6 weeks- IgM- positive, IgG for HSV1 was .10, and IgG for HSV2 was .09
2) Was suprised by the results, so had it redone 2 days later- IgM was positive, IgG for HSV1 was .12, and IgG for HSV2 was .10
3) Between 12-13 weeks total- IgM- positive, IgG for HSV1 was .15 and IgG for HSV2 was .08.

I realize the IgM tests are not accurate, for various reasons discussed in this forum.  In addition to these tests, I also got tested for EBV and came up positive for prior infection (IgM negative, but IgG was positive).  So, there might be some cross-reaction.  Do you agree?

My main questions are:
1) Would you agree with my doctor who is saying that my IgG for HSV1 is on the rise (he believes in the IgM accurately reflecting a recent infection) and that I should get tested again in 3-6 months to see if I have HSV1 or is a .05 variation (.10 to .15) not meaningful?
2) If, in fact, I do have oral herpes (which I don't think I do), besides not performing oral sex on my wife, are there any other precautions I need to take, given that she is 5 months pregnant?

Thank you.

[HmmmHSVneg]

A related discussion, If not HSV then what? was started.

[cortvi]

HI HOW ARE YOU
I got my regular anual check up 2 weeks ago and got tested for stds. for my suprise my dr told me everything came back o.k except that i tested positive for herpes.  I have never ever have any breakups in my mouth or my genital.
I'm devastaded and don't now what to do. I got the test results but they are so confusing....i'm so glad i found this forum i will really appreciate any help you can give me since i don't know which type i have (I or II)
here are my test results:

HSV,IgM I/II Combination    <0.91  ratio     0.00 - 0.90
                                    negative  <0.90
                                    equivocal 0.91 - 1.09
                                    positive   >1.09

HSV I/II  IgG              38.5H Index        0.0 - 0.8
                                    negative  <0.9
                                    equivocal 0.9 - 1.0
                                    positive   >1.0  
any Hepl a will really appreciate it.
which type do my results show type I or II
i will look foward for your response and thank you so muc again.

[metsox]

Doctor- thank you for the prompt response to my posting. It helps to my mind at ease.

[H. Hunter Handsfield, M.D.]

As you probalby realize now, "spending time with" someone with genital herpes, without sex, was not a valid reason to be tested for HSV.  Most likely it was on your mind because of your wife's pregnancy, but there was no risk of transmission (even if you had shared towels or eating utensils).  Anyway, your case is a good example why HSV antibody testing should be done only if there is valid clinical suspicion.

Your doctor obviously is not up to speed on understanding the HSV blood tests.  You are correct that the apparently positive IgM test is meaningless.  There is no cross reaction between antibody to HSV and EBV; your test showing past EBV infection is irrelevant to the HSV results.

1) The change in ELISA ratio from 0.10 to 0.15 means nothing.  Every value below 1.0 is just as negative as any other; if your results were say 0.10 and 0.50, it still would be meaningless.  Variations below 1.0 are not due to changing antibody levels, but fluctuations in the biochemistry of the test and/or differences in reagents from one test batch to the next.

2) You don't describe your symptoms of oral herpes, but your test results show you do not have it.  To be maximally safe, anybody with unexplained oral sores or other symptoms suggesting herpes should avoid performing oral sex on pregnant women, but there appears to be no risk for you.  You might also check with your doc (or a more herpes-knowledgeable provider) if those symptoms reappear someday.    

If your doc is skeptical about all this, tell him to search for papers on HSV serology in the medical literature, or specifically to search for research reports and reviews by Rhoda Morrow, the world's maven in HSV antibody testing.

Best wishes-- HHH, MD