Accuracy of IgG tests for herpes?

[pecan]

There seems to be so much debate and talk over the accuracy of igG testing.

My understanding was that after the window period which can be 4 months or more ( I guess we do not know how much more?) There is a chance of false positives, even still?

Also that again after the window period, that negatives were actually quite accurate.

 

Input from any experts?

 

I have over 6 IgG tests over the years that are all negative for hsv2 and postive for hsv1, which symptomsticvally matches my experience as I hasave had cold sores for a very long time.

[mr_hopp]

Hey @pecan!

You’re right—there’s definitely a lot of talk about the accuracy of IgG testing, especially with HSV-2. After the window period (typically 4 months, but it can vary), negatives tend to be reliable. However, false positives are possible, especially with results in the low positive range (1.1-3.5). That’s why a follow-up with a confirmatory test like the Western Blot is often recommended if you’re unsure. Since your IgG consistently shows negative for HSV-2, that’s a good sign!

It’s great you’re digging into this. Keep us posted on how the Western Blot goes!

[TwoWitsEnd]

Cold Sores? It is in over 90% of the population on the lip, in fact, it spread so much from kissing, that Ancient Rome had to ban the official greeting by lips that was so common back then among all peoples.

Since you have a history of cold sores, that certainly explains your hsv-1 antibody results.

So, you are just like the other 90% in the world with cold sores. I remember going to job interviews and seeing the cold sore on the Principals lips who I interviewed with. She was a very nice lady, but does not matter what ones career is etc, a cold sore is just a cold sore. 

The fact you have remained negative after so many months, this means what you have written. I do know some figures say 6 months on the tests, but I do not know how that compares to the 3 month results. I do not know if there are newer antibody tests that are more conclusive after 3 months or not. 

Either way, you have pinpointed why your hsv-1 showed positive, being due to your cold sore on your lips. Something that is just so common not only in USA but around entire world. 

 

[pecan]

I am already informed on cold sores.

I am asking more so about hsv2, and the info that I was given in regards to an igG test being accurate as far as negativws (as long as it's after the window period), where as a positive has more chance of being false.

Also, that I believed it was only during the window period that a false positive could occur. But I have now read that even after that window period, a false positive may occur.

[TwoWitsEnd]

If your IGG is negative at 6 months post risk, then you do not have it. I guess the issue indeed is with the low "positives" and there is some issue I believe because different labs use a different scale. That said, you stated your results were negative after the window period. 

[mr_hopp]

On 9/22/2024 at 1:10 PM, TwoWitsEnd said:

IGG is negative at 6 months post risk

Actually it's 16 weeks (4 months)

[TwoWitsEnd]

How accurate is IGG at 6 weeks? Is there any percentage?

[mr_hopp]

No, unfortunately not @TwoWitsEnd — IgG testing doesn’t get into granular percentages at a certain number of weeks because everyone’s immune response timeline is different. The body takes time to develop detectable levels of antibodies, and this varies from person to person. Some may show antibodies sooner, while others may not have enough for detection until later in the window period (up to 16 weeks or more). This variability makes it tough to assign a specific accuracy percentage at earlier stages like 6 weeks. Most data focuses on the 16-week mark for reliable results.

[TwoWitsEnd]

Okay, 16 weeks on a negative result seems to be the only threshold in which one can begin to first assume results are accurate then. Fair enough. 

[pecan]

This is form the CDC's website:

"After exposure, it can take up to 16 weeks or more for current tests to detect infection".

I have also been speaking with the research dept at U of Washington and they also said as much.

[pecan]

It is the "Or more...." than 16 weeks that I am curious about- after speaking with the research department at U of W, they said that pretty much after 6 months ( on the longer end) people will have antibodies. 

[NerdP423]

Excellent information, @pecan.

To add to this, my understanding of the Western Blot is that it's a little more accurate than the conventional IGG test at picking up HSV-2, but much more so at detecting HSV-1.

 

If you have no new worries about your health, I would say you don't even need the blot.