Well, we've been dealing with myco for years - so stubborn an it's still a mystery to me. It's DS's last infection to clear and it seems to wax and wane. He finally got his first recent negative test last month and then this month it went back up - UGH. He was also negative last fall and then either got reinfected or relapsed.
So, initially they tested for both Igg and Igm and then about
every 3 months they would test again - and it would still be high. Now they are testing monthly and only for Igm not Igg anymore. Igg is past evidence and Igm is current I believe.
From Mayo online: Positive IgM results are consistent with recent infection, although false-positives may occur (see Cautions).
A single positive IgG result only indicates previous immunologic exposure.
Significant concentrations of M. pneumoniae IgM and/or a four-fold increase in IgG levels between the initial sample and the convalescent sample indicate an active or recent M. pneumoniae infection. Increases in IgG, without IgM, can also be seen with a re-infection.
If neither IgM or IgG are present in detectable concentrations, then it means that a person being tested either does not have an active infection, has not had a mycoplasma infection (recent or in the past), or that the person's immune system has not produced antibodies in response to the microorganism.
Hope this helps a bit.
Parent of teen DS w/ CDC+ Lyme test Nov 2015, late stage Lyme + mycoplasma, bartonella, babesia. Currently treating with antibiotics/anti-malerials, multivitamin, magnesium, Charlotte's Web Advanced CBD oil.
Website I started: ParentsofLymeKids.com
aka Lyme Disease 101 for Parents