Quote:
Originally Posted by gianfrance
If I tested 1.1 for type 1 now, will this value to go down after sometime. I have totally not any symptom
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Using HSV IgG Antibodies as a screening test is not the best. Actually it is not even supposed to be used as a screening test.
The principle of antibody serology testing is this: the body produces antibodies specific to a bacteria or virus. So the presence of these antibodies suggests a current or past infection or vaccination. Example: You had a COVID infection last year. You test for COVID antibodies this year - it is positive. If you never had COVID, you test for COVID antibodies - it is negative. Sounds straight forward enough.
The problem with HSV antibodies is that there is a lot of cross reaction. In other words, the test machines mistake other antibodies for HSV antibodies. For example, if you ever had Chickenpox or Chickenpox vaccine, you could have antibodies that the machine will mistake for HSV antibodies.
That is why the lab has a cut off value. Think about it, if the above concept is true, then why should we say it is ok to have "a little bit of HSV antibodies"? Less than 1.1 is ok. That does not make sense. It should be zero.
So the lab sets a value above which it is considered "positive". This is NOT a digital concept. The fact is the higher the titer (amount of antibodies) the more LIKELY the test is a true positive. It is a statistical approximate. Some studies state that if the tier is > 3.0 the likelihood of a true positive is 99%. Not even 100%.
What is a better test to do is a Western Blot for HSV antibodies. This test is a lot more specific. In other words, if the WB test is positive for HSV 1 antibodies then the antibodies detected are truly HSV 1 antibodies.
Now the converse is also true. In other words, if the HSV antibody level is < 1.1 it does NOT mean the patient is NOT carrying HSV. I have seen many patients who have had HSV ulcers confirmed on PCR swabs but the blood IgG test remains "negative" (i.e < 1.1)
So where are we at? My 2 cents worth - do NOT do HSV blood screening if there are no symptoms. The blood test is not designed to be a screening test anyway. If there are symptoms, swab the ulcers for a PCR test. If you have to do a blood test, do a WB.
Hope that helps