[Question #5518] Herpes direct fluorescent enzyma test false positive with mononucleosis

22 months ago
Hi,

I fell sick 3 weeks ago (39-40°C fever, pain in the throat) so I did a blood test for Epstein Barr virus (I was suspecting a mononucleosis). I also did a test for toxoplasmosis, cytomegalovirus, HIV and herpes (direct fluorescent enzyma).  Turns out that the samples were positive for Epstein Barr and herpes 1 (IgM only, 1.6) and 2 (IgG and IgM, values >5).  I don't think I have so far herpes symptoms (never had cold sores around the mouth; I had one small single ulcer on one testicle but an infectiologist who saw it said it was not herpes and was more probably a chancroid; didn't generate any pain nor itching and doesn't look like the pictures of herpes sores I saw on the internet). I also did the same herpes test 2 months ago and it came back negative. I would like to know 1) if there is a chance that the herpes result is a false positive linked to the presence of the Epstein Barr virus, 2) if there is another more accurate test I can do, despite the absence of sore where to take samples from, 3) how long the mononucleosis is contagious and what I must do to prevent contamination. 

In details, the results are the following: Epstein Barr: EA-IgG=0.5, EA-IgA=1.6, EA-IgM=6.7, VCA-IgG=5.6, VCA-IgM=1.2, EBNA-IgG=3.1, EBNA-IgM=0.9.
Herpes 1 IgG: 0.5, IgM: 1.6; Herpes 2 IgG: 5.1, IgM: 8.5. All are considered reactive above 1.1.

Thanks in advance for your help!
Terri Warren, RN, Nurse Practitioner
Terri Warren, RN, Nurse Practitioner
22 months ago
I don't think you are in the US, is that correct?  but I do think you are using a test that has the same values as the one done in the US (>1.1 is positive).  You should ignore the IgM results as they are often falsely positive, but you cannot ignore an IgG value of 5.1.  While I have seen some false positives in that range and even higher, they are rare indeed.  The IgG is not positive due to the EBV being positive.  The test you had done is type specific and only looks for HSV.  And honestly, the sore concerns me.  Again, I don't know where you live but in most places in the world, herpes is far more common than chancroid.  The most accurate antibody test for herpes is the western blot, done only at the University of Washington.  That would eliminate the possibility of a false positive, for sure.  Where do you live?

Terri
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22 months ago
Hi, 

Thanks a lot for your quick, complete and clear answer, you confirmed what I feared... You guessed right, I live in Mexico.  I have some follow up questions if you don't mind:
- the lab where I did the test is proposing me to do a PCR on a blood sample (they say  they will send it to the US). I thought PCR was only done with a swab, was I wrong?  I'm trying to do a Western Blot but I am struggling to find a lab in Mexico City.
- if this herpes diagnosis is confirmed, is there any clinical trial I could enroll in? Do you know of any recent successful clinical trial for a treatment?
- do you know where I could find statistics on the probability of contamination of a sex partner, depending on the type of sexual activity, the use of a condom and the fact of taking or not daily antiviral drugs?
- are there any known side effects of taking daily anti-herpes drugs?
- do you have any guidance on what to do / not to do to avoid contaminating other people with mononucleosis (and how long will I be contagious?)
- could I send you a picture of the sore to have your professional opinion on whether or not it is herpes?
Thanks for your help.
Terri Warren, RN, Nurse Practitioner
Terri Warren, RN, Nurse Practitioner
22 months ago
NO!  PCR from blood is totally useless and inappropriate. Herpes virus is almost never in the blood and the PCR looks for virus, not antibody
You will not find a lab in Mexico (I don't think) that will do the western blot.  That is the University of Washington.  If you can get a serum separator tube of blood drawn and spun, I can work with you to get the blot here in the US
There are usually NO side effects from taking antiirals
You may have antibody to EBV from an infection long ago - I don't have advice about not transmitting EBV at this time
If you want me to help you with the blot, we can schedule a video conference and at the time, review documents you might have about herpes infection in you.

Terri
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22 months ago
Hi,

Thanks for your reply.  I would indeed really appreciate some help on how to do this Western Blot test from here, please let me know how we can get in touch.
Sincerely,
Terri Warren, RN, Nurse Practitioner
Terri Warren, RN, Nurse Practitioner
22 months ago
Go to westoverheights.com and click on the box that says video conferencing.  That will take you to evisit and they will set up an account for you and you can schedule an appointment to meet with me and we'll get going on the order for the blot

Terri
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