What is the difference between IGG and IGM? Will this indicate past or present infection?
Posted by minimonkey (Member # 8693) on :
I'd like a good answer to that one, too. My understanding, and I'm not at all sure this is correct, is that lyme generally shows up on the IgG first, and longer standing infections show up mostly on the IgM -- Per my NP, a positive on either one merits treatment.
Most infections, I believe, go the other way -- IgM first, and then IgG later, so this confuses ducks to no end.
Posted by chetesrus (Member # 10010) on :
www.igenex.com has a description of IgG and IgM. Click on "Western Blot" under "Lyme Disease".
Posted by Aniek (Member # 5374) on :
IGM is a sign of recent or current infection. Ideally, the IGM will go down with treatment.
IGG is a sign of exposure. It can be a current or past infection.
A neurologist I saw was very surprised I had a positive IGM and negative IGG. In most infections, you don't see that. Especially after 20 years of infection. I believe you see it in Lyme because of the suppressed immune response.
Posted by minimonkey (Member # 8693) on :
thanks, Chetesrus --
According to that, I believe, the IgM is the more specific and sensitive of the two tests, and a positive on the IgM indicates either new-ish or long-standing, active infection.
Syphillus or rheumatoid factor cross reactivity is a possible confound, and could cause a false positive. (Then again, according to my NP, lyme can cause high rheumatoid factor, as well.)
Posted by Lymetoo (Member # 743) on :
The answer is right here. Look for the highlighted areas:
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