[Question #566] Herpes Lab Results

42 months ago

I’m a female in my 20s. I was experiencing symptoms of swollen and painful lymph nodes on the right side of my neck accompanied with a sore throat, chills, fever, and fatigue.  I ended up going to an urgent care and a rapid strep throat test was done. The test result was negative and I was told it was probably a bacterial infection. I was prescribed an antibiotic and by the fourth day, I noticed a big improvement.

I followed up with my medical doctor shortly after and lab blood work was ordered for me. Per my request, I had asked if I could get a herpes blood test along with my other lab work. This decision had absolutely nothing to do with my current status or in the past. I never had any questionable sores around my mouth or genital area. I understand that it’s not recommended to screen for herpes if there’s no reason to, but just to be cautious, I wanted the test. An HSV-1 igG, HSV-2 igG, and HSV igM test was ordered.

Shockingly, my HSV igM test result came back positive. However, my HSV-1 and HSV-2 igG test results came back negative. I did a lot of research after finding out my lab results. I was surprised to find out that HSV igM testing isn’t recommended as part of herpes testing. Furthermore, HSV igM testing can produce false-positive results and cross react with other viruses. I have a past history of chicken pox and shingles. Also, I recently tested for mono and was negative for the Epstein Barr VCA igM. However, I was positive for the Epstein Barr VCA igG and the lab result for this particular antibody was high. Other than kissing, I have only engaged in receiving oral sex from two male partners. The amount of time between my last partner encounter and the herpes blood testing was 4 weeks and 3 days.

Based on this information, do you think I acquired an acute infection of herpes due to my HSV igM test result being positive? Also, do you think the symptoms I was experiencing have any correlation with a herpes outbreak? Lastly, is it possible that my HSV igM test could be a false-positive result?

If you could please give me your expert opinion and any additional insight on this situation, I would greatly appreciate it. Thank you!

Terri Warren, RN, Nurse Practitioner
Terri Warren, RN, Nurse Practitioner
42 months ago
I do NOT believe that you have a newly acquired herpes infection, based on your IgM value.  I cannot tell you how annoying it is for clinicians to do that test!  Damn!  It upsets people needlessly and is so clearly not recommended.  The CDC says about herpes antibody testing the following:

Type-specific HSV serologic assays might be useful in the following scenarios: 1) recurrent genital symptoms or atypical symptoms with negative HSV PCR or culture; 2) clinical diagnosis of genital herpes without laboratory confirmation; and 3) a patient whose partner has genital herpes. HSV serologic testing should be considered for persons presenting for an STD evaluation (especially for those persons with multiple sex partners), persons with HIV infection, and MSM at increased risk for HIV acquisition. Screening for HSV-1 and HSV-2 in the general population is not indicated.

I'm not clear that receiving oral sex from two different people constitutes "multiple partners" but I don't think it was a bad thing to do to get tested.  If you have only received oral sex in your lifetime, then your risk for HSV 2 infection just isn't there.  And you are concerned about oral symptoms - not genital ones and that's where you would be showing symptoms if you got an STD from these encounters. While it is possible that you could have acquired HSV 1 from kissing, that to me seems very unlikely since you aren't having any sores or blisters at all in the oral area.   If you were my patient, I would suggest that you completely ignore the IgM test in this situation.  Another thing is that you are improving dramatically while on antibiotics which also suggests a bacterial origin or even a non-herpes viral infection that is getting better with time.  Without any oral lesions, herpes would not be on my list of things to worry about.

Terri
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42 months ago

Terri, thank you so much for your very helpful response! You have definitely eased my anxiety and I appreciate that. I do have additional questions that I would like to ask:

1.       1. My doctor recommended having another HSV-1 and HSV-2 igG test. How many weeks or months do you think I should wait to repeat this test? Should I base this from my last sexual exposure from the male partner or from my last blood test?

2.       2. From your clinical experience and knowledge, what can trigger a false-positive HSV igM test?

3.       3. Why is igM testing not used with herpes infections if it is used to determine acute onset of other infections?

4.       4. I watched the herpes testing video on this website and Dr. Handsfield had mentioned that igM testing often doesn’t proceed igG testing. So does that mean igG antibodies show up first rather than igM antibodies in someone who is infected with the herpes virus?

5.       5. What is the risk of someone passing the HSV-1 strand through kissing if asymptomatic?

Terri Warren, RN, Nurse Practitioner
Terri Warren, RN, Nurse Practitioner
42 months ago
You base the test timing on the last contact with the male partner.  While IgM is accurate in helping to sort out some new viral infections (like hepatitis) the QUALITY of this test is poor and also IgM is regenerated with recurrences some of the time AND it has many false positives in my experience - more false positives than true positives, by far!  A false positive would be a positive IgM for a type that never becomes positive by IgG.  It is also possible for IgG and IgM, with herpes, can show up at the same time, yes.  We don't have a statistic on HSV 1 transmission - either with or without symptoms, actually. 

Terri
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42 months ago

Thank you again for your response back Terri! I have been very worried and anxious with the situation that I’m in, so I appreciate you taking the time to help me.

Terri Warren, RN, Nurse Practitioner
Terri Warren, RN, Nurse Practitioner
42 months ago
My pleasure!  I'm not very worried about your situation at all, honestly.  I'm guessing things will be just fine.

Terri
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