False Positives?

[Evlos99]

Hi Terri,
I recently had testing for HSV 2 and am worried/confused about the results.  I had a protected encounter on 11/22/2013 and was tested more than 7 weeks later in mid-January 2014 and got negative results for both HSV 1 and 2.  In the meantime, I developed itching on my penis and slight pain during erection.  I also noticed an unusually large amount of pre-ejaculate during masturbation.  I went to my physician, who did a physical exam but did not see any signs of HSV and thought it was probably a yeast infection.  The itching/pain and pre-ejaculate issues resolved a few days after my doctor's appointment at the end of January, and I subsequently had two encounters in February 2014 with different people (2/11/2014 and 2/25/2014).  I was tested again 6 weeks after the last encounter and got a low positive result with a Captia IGG test for HSV 2 (1.81) (negative for HSV 1).  I did another test a week later and also got a low positive result with a Captia IGG test for HSV 2 (1.56) (negative again for HSV 1).  My last partner in February recently got tested and was negative for everything.  I am now completely freaked out.  I haven't had any blisters, redness or other outbreaks but have had transient itching on my penis. I am wondering whether it's likely that my testing in January was a false negative.  Or, more hopefully, what are the chances that both my recent tests showing low positives were actually false positives.  And what should I do now?  Western Blot?  Thanks for your help and advice.

[Terri Warren, RN, Adult Nurse Practitioner]

I don't believe there is a reason to have another western blot, no.  In my experience, many people who have an indeterminate test result stay exactly that way through repeat testing.  The encounter in November is now irrelevant.  

Terri

[Evlos99]

Thanks, Terri.  I may give Rene a call.  In the meantime, is there any reason to take the WB test again?  And does this mean that the November 2013 encounter is irrelevant, since it's been about 5 months?  Thanks!

[Terri Warren, RN, Adult Nurse Practitioner]

Those darn intederminates!  I that those.  And they are so common lately for the low positives.  You could also have some protein of your own (not herpes) that is tripping this test artificially.  We are doing a study this summer on a new test for herpes and we will be focusing on indeterminate results people.  If you would like to be included, please call my office and speak with Rene.  She will take your contact info.  

However, in your situation, because your intercourse was protected and most people who might have infected you recently are not positive, I'm guessing you are more likely negative than positive but I can't be certain.

Terri

[Evlos99]

Hi Terri,
I have some follow up information.  I went ahead and got blood drawn for the WB on April 28th and just got my results back.  Negative for HSV1 (consistent with IgG) but indeterminate for HSV2.  It noted "atypical reactivity" that "may or may not be due to HSV-specific antibody.  So my question is: what next?  I assume this means that I did not catch anything from my November 2013 encounters, since it's been much longer than 12-16 months.  So if I'm actually positive, I would have to have caught it from my February encounters.  One of those people already tested negative and the other is my long-time partner, who I doubt is sleeping around (but you never know).  Do you think I need to get WB tested again?  Is there another test I can/should try instead?  Thanks for your help!

[Terri Warren, RN, Adult Nurse Practitioner]

For greatest accuracy, I would wait 16 weeks from that encounter or try to get her to get tested.  Likely telling her you have a positive test after having had a negative one would trigger her to be tested.

Terri

[Evlos99]

Thanks very much, Terri.  That is very helpful and certainly puts my mind at ease.  One follow up question: I actually had 2 different partners in February.  Only one has been tested and was negative.  The other has not been tested, has a history of cold sores, but to my knowledge no genital symptoms.  Would it still be appropriate to do WB now?

Thanks!

[Terri Warren, RN, Adult Nurse Practitioner]

I think it is likely that you have a false positive IgG for HSV 2 but can't really be certain without further testing, yes, western blot.  I don't believe the itching or pre-ejaculate has anything to do with herpes, if indeed you are infected at all.  And as you know the IgM is not a useful test but at least you don't need to worry about it being falsely positive.

Clearly, herpes testing is not a perfect science at this point.  I sure wish it was a perfect science!  Sometimes people have their own cellular proteins that can make a test for herpes look positive when it is not, it is simply picking up people's normal "stuff".

Since the February partner tested negative, I think you are fine to get confirmatory testing now.  You can either order the test kit from the University of Washington directly for your provider to draw and send back or our clinic can help you with that order.  

My guess is that you will confirm as negative but I'm not sure enough to have you forego the western blot.  

Does that give you the information that you need?

Terri

[Evlos99]

A few more facts that might be relevant.  First, the itching did not start until about 5 weeks after my November 2013 encounter (end of December or early January).  I don't remember any other symptoms before that.

Second, my doctor also ordered an IGM test in April 2014 along with the last IGG.  Results for IGM were negative for both HSV 1 and 2.  My doctor said this indicated the infection was probably from November 2013 rather than February 2014.

Thanks again for your help!