HSV2 Igg tests low positive

[curiousGeorge]

So, recently diagnosed, never had obvious symptoms (except for occasional soreness/rash that I have always explained by just mechanical action :-/ ). My HSV1 Igg is >22, but HSV2 came back at 1.7 and 1.4 (both done within a week). My GF is freaking out obviously and wants me to request Western Blot to be done.

 

Question: do Igg tests still have cross-reactivity between HSV1/HSV2? Seems like Igm tests were highly susceptible, but what about Igg?

Does it make sense to request the WB? Since its only done in UoW this will be a challenge. How specific is the HSV2 Igg?

 

Thanks!

[ihaveittoo]

Not sure about cross reactivity, but the IgG is a more reliable test than the IGM. That being said, an IgG result below 3.5 has a 40% chance of being a false positive. A WB makes perfect sense in this situation. Contact Westover Heights about arranging the WB.

[curiousGeorge]

Thanks! Unfortunately seems like Westover Heights can no longer do WB - there is a message on their page saying they're looking for a new lab partner. I'll have to talk to my doc about it.

[MMissouri]

I was just looking at a test result of a patient who had HSV IgG testing and there was a note at the bottom about cross reactivity. I didn't pay much attention, but the mention of it makes me think it's still possible.

 

If it makes you feel better, I just took this off of quest diagnostics:

 

The HSV-2 IgG Western blot assay has historically been considered the gold standard for identifying HSV-2 IgG reactivity. However, Ashley-Morrow et al have clearly demonstrated that the HSV-2 IgG Western blot is less sensitive than the HerpeSelect HSV-2 IgG ELISA for detecting IgG seroconversion following newly-acquired HSV-2 infection: the median interval between symptom onset and IgG seroconversion was 21 days for the HerpeSelect ELISA versus 68 days for the Western blot assay.3 There is thus a window of approximately 47 days in which the Western blot assay may give false-negative confirmatory results. In contrast, true-positive specimens in this window are positive (>60% inhibition) in the HSV-2 IgG inhibition assay. In addition to increased sensitivity, the turnaround time for the inhibition assay is shorter than that of the Western blot assay.

 

Hope that helps.

[HikingGirl]

I had a low IgG value for HSV2 and a higher value for HSV1, like you. The Western Blot confirmed I do have HSV2. It's expensive, but in my mind, it's worth the hassle to be sure. The six weeks between my initial diagnosis and the Western Blot made me a nervous wreck! At least now I can move forward.

[camilo]

What was your "low" Igg score Hiking Girl?

[HikingGirl]

3.27

[camilo]

Thank you